Your armpit, also known as the axilla, contains a large collection of lymph nodes, hair follicles, and sweat glands. A number of things can cause pain in the hollow created by your chest wall, muscles ...

Medically reviewed by Doru Paul, MD Key Takeaways An armpit lump, also called axillary lump, can be a symptom of breast cancer.A healthcare provider should check any hard armpit lump that doesn't ...