Nipple pain can be caused by tight clothing, menstruation or mastitis. 1. Wearing clothes that are too tight: You may be wearing underwear that is too tight, leading to impaired local blood circulation, causing nipple pain when touched. 2. The onset of menstruation: after some women’s menstruation, the level of estrogen in the body will increase, which may cause pain in the breasts, and when you touch the nipple, there will be obvious pain. 3. Mastitis: Mastitis can be caused by bacterial infection of the breasts due to lack of attention to breast hygiene and improper breastfeeding posture during breastfeeding. It may also be accompanied by swelling of the breasts. In addition, breast trauma, breast hyperplasia, breast cancer, nipple eczema and other diseases may also lead to similar symptoms, it is recommended to consult a doctor in a timely manner to clarify the cause of the disease, to target treatment.