There are mainly physiological and pathological factors: physiological factors can be found in the developmental period or physiological period due to endocrine hormone disorders, causing local congestion and enlargement of the nipple, which can cause slight pain when stimulated by the outside world, which is a normal physiological phenomenon. Pathological factors include acute inflammatory changes in the nipple, including nipple trauma and acute mastitis, when external forces act directly or indirectly on the nipple, which can cause local tissue damage to the nipple and acute inflammatory changes, resulting in severe pain in the nipple, and the appearance of the surrounding skin in purple or in spots. In addition, when suffering from cystic hyperplasia, breast swelling and discomfort may occur, and when the pain increases, it may spread to the nipple and cause nipple pain. When there is pain in the nipple, you should go to a regular hospital for breast surgery or general surgery in a timely manner to identify the cause and target treatment to cure it.