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 ...

Add Yahoo as a preferred source to see more of our stories on Google. Pulled Muscle or Heart Attack? How to Tell the Difference in Chest Pain Chest pain can be disconcerting, but it's important to ...