If the breast pain disappears suddenly, it may be due to menstruation. Before menstruation, breast pain may occur mainly because of the imbalance of hormone secretion in the body, such as high secretion of estrogen and relatively low secretion of progesterone, so there will be localized breast pain, emotional changes, insomnia and so on. If you are going to have your period, the estrogen and progesterone in your body will drop accordingly, so the localized swelling and pain in your breasts will disappear. It is also advisable to go to the hospital after the menstrual period for examination to exclude the possibility of other diseases.