Breast pain after menstruation may be caused by pregnancy or breast disease, as follows: 1. Pregnancy: If your period is very normal, and you do not take contraception during sex during menstruation, for the breast pain that occurs after menstruation, the first thing to rule out is pregnancy. Early pregnancy will produce continuous breast pain after menstruation in some women of childbearing age; 2. Breast diseases: such as breast hyperplasia, cystic lesions of the breast, and even malignant diseases of the breast, will also produce breast pain after menstruation. Therefore, if breast pain persists after menstruation, you need to go to the gynecological department of the hospital in time to get a clear diagnosis and active treatment.