Why do I feel lumps in my armpit?

The armpit is busy territory - it hosts a cluster of lymph nodes that drain the arm, chest wall, and breast, and those nodes swell whenever they are working. The NHS describes swollen glands as tender, painful lumps that appear in the neck, chin, armpits, and groin, usually a sign the body is fighting an infection, and usually gone within 1 to 2 weeks. The armpit version is often traceable: a cut, ingrown hair, or infected spot anywhere on that arm or hand, a recent shaving nick that got angry, or any bug going around. MedlinePlus's armpit lump page lists the common causes - swollen lymph nodes, infections, and cysts - and notes that shaving and antiperspirants can cause small painful lumps, especially in people new to shaving. Blocked sweat glands and simple cysts account for most of the rest. The reassuring pattern is tender, softish, movable, and shrinking over a week or two as the trigger clears. The check-it pattern: a lump that is hard, fixed in place, painless, growing, or still present after 3 to 4 weeks with no infection to explain it - lymph nodes are filters that can also catch tumour cells, so unexplained persistent armpit lumps belong in front of a GP, and women should treat any new armpit lump as a reason for a breast check too. Also on the list: lumps arriving with drenching night sweats, unexplained weight loss, or fever. Do not prod it daily - squeezing keeps it angry. Pymander is a free AI doctor, 24/7 by text, that can help you decide how quickly yours needs looking at.