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 ...

Around a month ago, I ran a 5K and followed it with a full-body dumbbell workout. Halfway through a set of renegade rows, I felt something go in my back. It didn't hurt too much immediately, but it ...