The armpit is a pyramid-shaped hollow between the edge of the chest muscle at the front, the edge of the broad back muscle at the back, the chest wall on the inside and the upper arm on the outside. In it lie 20–40 lymph nodes in several groups, which receive lymph from the whole arm, the hand, the breast, the skin of the chest and the upper part of the abdomen; they become tender and swollen when something in that area is infected or inflamed, and they react to vaccinations in the arm. The large vessels and nerves to the arm also run there, the tendon attachments of the chest muscle and back muscle (which are overloaded by chin-ups, push-ups, throwing and carrying), and a portion of breast tissue in both women and men, which can swell and be tender hormonally. The skin of the armpit is warm, moist and full of sweat and sebaceous glands and hair follicles, and it is shaved, deodorised and rubbed, which makes inflamed hair follicles, boils and irritation very common. All of this hurts in slightly different ways: a node feels like a tender, mobile bean or pea deep in the hollow; a muscle or tendon is tender in the front or back wall of the armpit and hurts with arm movements; a skin inflammation is superficial, red, warm and tender to touch; breast tissue is diffusely tender and swollen, often both sides and before a period. Most of it is harmless and passes in days to weeks. What should be examined is a lump that is hard, painless, fixed and doesn't go back, especially together with a lump in the breast, a one-sided swollen arm, fever without infection or night sweats. Here are the causes, how to tell them apart, when to seek care, and what you can do yourself.
What armpit pain can be
| Cause | How it feels | What triggers it | What helps |
|---|---|---|---|
| Swollen lymph node (reactive) | A tender, soft to firm, mobile bean or pea deep in the armpit, sometimes several; tender to press and when the arm rests against the body | Infection or wound on arm, hand or chest, eczema, infected hair follicle in the armpit, a cold, glandular fever, vaccination in the arm (one to several weeks), mastitis when breastfeeding | Treat the cause; the node goes back within two to four weeks; don't press or massage it. See swollen lymph nodes |
| Overworked muscle or tendon attachment | Tender in the front wall of the armpit (edge of the chest muscle) or back wall (broad back muscle, teres major), worse with arm movements, bench press, chin-ups, throwing, carrying; no lump, sometimes a taut band | A new or hard workout, moving house, painting ceilings, racket sports, swimming | Light movement, heat, stretching of chest muscle and back, cupping the edge of the muscle; heals in one to three weeks. See chest muscle pain |
| Inflamed hair follicle, boil, sweat gland inflammation | Superficial, red, warm, tender lump or spot in the skin; with a boil throbbing and tense; with hidradenitis suppurativa recurrent deep boils and scars in armpits and groins | Shaving, waxing, deodorant, sweat, friction, tight clothes | Warm compresses for 15 minutes several times a day, wash with mild soap, don't squeeze, rest from shaving; your doctor for a boil that grows, fever, spreading redness or recurrent boils |
| Irritation from deodorant, shaving or clothes | Superficial stinging, itching, redness, small bumps over the whole armpit, both sides | New deodorant or antiperspirant, perfume, shaving against the hair, synthetic clothes | Pause the product, wash with water, unscented moisturiser, shave with the hair or trim; dermatologist for eczema that doesn't clear |
| Breast tissue | Diffuse tenderness and swelling in the lower part of the armpit towards the breast, often both sides, cyclical before a period; when breastfeeding a tender, hard lump (blocked duct) or red warm swelling with fever (mastitis) | Hormone cycle, pregnancy, breastfeeding, the pill, menopausal hormone therapy | A good bra, heat, light lymphatic massage towards the armpit; when breastfeeding continued feeding and heat, your doctor with fever. A distinct lump in the armpit or breast that doesn't vary with the cycle should always be examined |
| Nerve from the neck or compression in the armpit | Burning, radiating pain or numbness from the armpit down the inside of the upper arm, sometimes up towards the shoulder blade | Disc herniation in the neck, thoracic outlet syndrome, crutches or a heavy bag pressing in the armpit, sleeping with the arm overhead | Remove the pressure, neck and posture exercises; see arm pain and nerve pain |
| The shoulder | Pain deep in the armpit and the front of the shoulder when lifting the arm, often night pain | Impingement, frozen shoulder, biceps tendon | See shoulder impingement and frozen shoulder |
| Shingles | Burning, stabbing pain in a band from the back through the armpit towards the chest on one side, followed after a few days by blisters | Reactivation of the chickenpox virus, often with stress or a weakened immune system | Your doctor quickly: antiviral treatment within 72 hours |
| Lymphoedema in the arm | Heaviness, tightness and swelling in arm and hand, sometimes tenderness in the armpit | After surgery or radiotherapy to the armpit lymph nodes (breast cancer treatment) | Lymph therapist, compression, lymphatic massage as instructed; see lymphoedema |
| Cyst or fatty lump | Soft, mobile, painless lump under the skin that has been there a long time and doesn't change | – | Harmless; show it if it grows, becomes tender or is larger than a few centimetres |
| Lump that should be examined | Hard or rubbery, painless, fixed to the underlying tissue, growing, doesn't go back in four to six weeks, without an infection to explain it | Lymphoma, spread from breast cancer or skin cancer on the arm | Your doctor within a week; most still turn out to be benign |
When to seek care
- Same day: a red, warm, rapidly growing swelling in the armpit with fever or spreading redness (abscess or skin infection); an arm that has quickly become swollen, heavy, warm or blue-red (blood clot in the arm veins); mastitis with high fever when breastfeeding; blisters in a band on one side (shingles, treatment within 72 hours); sudden severe pain in the armpit and chest with breathlessness or cold sweat (emergency services).
- Your doctor within a week: a lump in the armpit that is hard, painless, fixed or growing; a lump that remains after four to six weeks without an infection explaining it; a lump in the armpit together with a lump or change in the breast (in women and men); swollen nodes in both armpits without infection, or together with night sweats, weight loss, fever or itching; recurrent boils in the armpit (hidradenitis can be treated); swelling in the arm after breast cancer treatment (lymphoedema should be treated early).
- Wait and see, two to four weeks: a tender, mobile node after infection, wound, eczema or vaccination; muscle soreness after training; skin irritation after shaving or deodorant; cyclical tenderness before a period. If it doesn't improve: book an appointment.
The examination at the doctor's is simple: the doctor feels the armpit, arm, breast and neck, and takes blood tests and an ultrasound if needed. In women over 40, mammography is often part of investigating an armpit lump. Remember that even lumps with "worrying" features usually turn out to be benign; the point is that they should be examined.
What you can do yourself
With skin problems
Wash with lukewarm water and mild unscented soap, pat dry, rest from shaving for a week and then shave with the direction of the hair with a clean blade, switch to an unscented deodorant without aluminium if the skin reacts (or try without for a few days), wear cotton next to the skin, and apply warm compresses to an inflamed hair follicle for 15 minutes three times a day until it drains by itself. Don't squeeze: it spreads the infection deeper. Recurrent boils in the same places are not poor hygiene but a skin disease (hidradenitis suppurativa) that your doctor and dermatologist can treat.
With muscle and tendon problems
Keep moving the arm within what doesn't hurt, avoid what triggered it for one to two weeks (pressing exercises, chin-ups, throwing), warm with a shower or heat pad for 15 minutes, stretch the chest muscle in a doorway and the broad back muscle with the arm overhead leaning to the side, 30 seconds × 3, and cup the edge of the muscle: glide the mini cup with light suction along the edge of the chest muscle from the breastbone out towards the shoulder and along the back wall of the armpit from the waist up towards the shoulder, one minute per line. Never cup inside the armpit itself, where nodes, vessels and nerves lie superficially. See muscle knots and trigger points.
With a swollen node
Leave it alone. Don't press, massage or cup it; treat what caused it (the wound, the eczema, the infection), rest and drink, and give it two to four weeks. Tenderness when the arm rests against the body is eased by a soft cotton pad in the armpit and by holding the arm slightly away from the body. Once the infection has healed and the node is only slowly going back, light lymphatic massage of the surroundings can help flow through it: circle gently with the palm in the armpit without pressure, then stroke from the hand up along the inside of the arm towards the armpit, and from the side of the chest upwards towards the armpit, ten light strokes each. The technique is in lymphatic massage at home and the principles in how the lymphatic system works.
Lymphatic massage and cupping towards the armpit when you are well
The armpit nodes are the station all lymph from the arm and breast goes to, and when you want to keep the flow moving (a heavy, swollen arm after a day with the arms down, tension in shoulder and chest muscle, tender breast tissue before a period) you direct all massage and cupping towards the armpit, never into it. Open first: five deep belly breaths and ten gentle circles with the palm in the armpit. Then glide the mini cup with minimal suction from the wrist up along the inside of the forearm and upper arm towards the armpit, 2 minutes, and the dynamic cup from the side of the chest and from the edge of the chest muscle in towards the armpit, one minute per line, with light pressure. Never on breast tissue in someone with lumps that haven't been examined, never on an arm with lymphoedema without the lymph therapist's instruction, never over a swollen node, rash, boil or wound, and not with fever; see when to avoid cupping. Routines in the cupping programme for arm and shoulder and lymphatic health with cupping.
Read more
Swollen lymph nodes, the lymphatic system, lymphoedema, arm pain, chest muscle pain and lymphatic massage at home.
Frequently asked questions
Why does my armpit hurt?
Most common is a tender lymph node reacting to infection, a wound or eczema on arm, hand or chest, or to a vaccination; an overworked chest or back muscle after training or carrying; an inflamed hair follicle or boil after shaving; irritation from deodorant; or tender breast tissue before a period. Less often nerve involvement from the neck, the shoulder, shingles or lymphoedema. A hard, painless lump that doesn't go back should always be examined.
What does a swollen lymph node in the armpit feel like?
Like a tender, soft to firm, mobile bean or pea deep in the hollow of the armpit, sometimes several, tender to press and when the arm rests against the body. It comes together with an infection, a wound or a vaccination in the arm and goes back in two to four weeks. A node that is hard, painless, fixed, growing or remains after six weeks without explanation should be shown to a doctor, as should a node together with a lump in the breast.
When should I seek care for a lump in the armpit?
The same day for a red, warm, rapidly growing swelling with fever, a swollen heavy arm, blisters in a band or mastitis with high fever. Within a week for a lump that is hard, painless, fixed or growing, that remains after four to six weeks without infection, that comes with a lump in the breast, or with night sweats, weight loss or unexplained fever. A tender, mobile node after infection or vaccination can wait two to four weeks.
Can you massage or cup the armpit?
Not into the armpit, and never on a swollen node, boil, rash or a lump that hasn't been examined. What you can do is direct light lymphatic massage and cupping towards the armpit: from the hand up along the inside of the arm and from the side of the chest and the edge of the chest muscle in towards the armpit, with minimal suction, after opening with deep breaths and gentle circles in the armpit. Not with lymphoedema without the lymph therapist's instruction, not with fever.
Can armpit pain come from the breast?
Yes, breast tissue extends up into the armpit in both women and men, and it can swell and be tender cyclically before a period, during pregnancy and breastfeeding (blocked duct, mastitis) and from hormone therapy. Cyclical, diffuse tenderness on both sides is harmless. A distinct lump in the armpit or breast that doesn't vary with the cycle, skin changes on the breast or discharge from the nipple should always be examined, regardless of age and sex.
Related guides
Written by Curam. Last updated 17 October 2026. This is general self-care information and does not replace medical care. For sudden, severe or unusual symptoms, contact your doctor. Talk to your doctor before cupping if you are pregnant, take blood thinners or have a condition affecting skin, blood vessels or blood.
