Breasts here refers to the breasts, before the onset of menstruation may appear breast pain, but not absolute, there may also exist breast hyperplasia, pregnancy and other conditions. 1. menstruation: before menstruation due to the body’s hormone level changes, estrogen and progesterone may exist on the breast ducts of strong stimulation, and then appear breast swelling and pain, generally do not need to pay too much attention to the situation. 2. Breast Hyperplasia: Breast pain may also be caused by breast hyperplasia, which is often accompanied by localized hard lumps, it is recommended to go to the hospital for ultrasound examination to determine the cause of the intervention. 3. Pregnancy: Breast pain may also be due to the presence of pregnancy, mainly because pregnancy can make the body appear high concentrations of estrogen and progesterone, there is a strong stimulation of the body, and then breast pain symptoms, it is recommended to go to the hospital in time for hCG examination to determine. Breast pain may also have other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, give targeted treatment or treatment.