The common cause of nipple pain is nipple inflammation, the nipple belongs to the duct of the breast and the external opening of the organ. When the nipple is infected by bacterial invasion, it is easy to cause local inflammation, and the nipple is rich in nerve endings, which can manifest as swelling and pain in the nipple, so usually pay attention to good nipple hygiene. As the breast and nipple protrude from the body surface, they are very vulnerable to trauma such as squeezing and impact, and soft tissue injury to the nipple will cause significant pain and swelling of the nipple. Cystic hyperplasia of the breast will present with periodic breast pain, and some patients will also have nipple pain, which is due to overgrowth of breast tissue and the discomfort of breast swelling and tingling. Nipple pain can also be caused by nipple cracking that occurs when the baby bites during breastfeeding. If the nipple pain is more severe, try to visit the hospital in time to check and confirm the diagnosis and treatment.