Breast pain during menstruation is considered to be caused by physiological factors, but the possibility of breast hyperplasia and breast cancer cannot be ruled out. 1. Physiological factors: During menstruation, the hormones in the body are unstable and estrogen will gradually increase, which will lead to breast swelling and pain, which can usually be relieved after menstruation. 2. Breast hyperplasia: related to endocrine dysfunction, mainly breast lumps, breast nodules, mostly related to menstrual cycle. 3. Breast cancer: the cause is unknown and may be related to heredity. Patients may have breast pain, breast lumps, breast overflow and other uncomfortable symptoms, and in severe cases, orange peel-like manifestations may also occur. Breast pain during menstruation can also be caused by trauma, intercostal neuralgia and other factors, after excluding physiological factors, should go to the hospital in a timely manner to avoid delay.