mastalgia
(mas-TAL-juh)
Pain or discomfort in one or both breasts. The pain can be mild or severe and affect one area of the breast or the whole breast, including under the arm. It may also come from nearby muscles or joints outside the breast. Mastalgia in women is most often caused by hormone changes before and during the menstrual cycle. It may also be unrelated to the menstrual cycle, with causes that include pregnancy, breastfeeding, smoking, too much caffeine or fat in the diet, certain medicines, breast surgery, injury to the breast or chest wall, or certain breast conditions. It is rarely caused by breast cancer. Mastalgia can occur in both women and men. Also called breast pain.