If you have sore nipples after your period, you may have mastitis, which can cause sore nipples and also redness and swelling. When a woman suffers from breast nodules or breast hyperplasia, nipple pain may also occur. Thirdly, nipple pain after menstruation is mostly caused by the change of hormone level in the body, especially after menstruation, the estrogen in the body will increase, and the estrogen will promote the development of breast ducts, which will also lead to the occurrence of nipple pain. Women who have nipple pain after menstruation can be relieved by proper massage or wearing loose underwear, and if they can’t be relieved, they need to go to the hospital to do breast ultrasound for diagnosis so as not to affect the treatment of the disease.