Rib pain on the lower side of the nipple may be caused by sebaceous cyst, costochondritis, soft tissue injury and other diseases. 1. sebaceous cyst: it is because the sebaceous gland in the process of secretion, the secretion of the mouth is blocked, sebum in the case of excessive secretion, it will spread to the surrounding tissues, the formation of a cystic change, the enlargement of the surrounding nerves will be compressed to cause pain, it may appear in the lower side of the nipple. 2. costochondritis: costochondritis is a kind of sterile inflammation, the inflammatory factor will stimulate the nerves and lead to pain, which may appear in the position of the rib cartilage. 3. soft tissue injury: as a result of soft tissue injury, localized swelling and increased pressure, potassium ions are released, leading to pain. Rib pain on the lower side of the nipple may also be seen in pleurisy, fasciitis and other diseases, if the symptoms of rib pain on the lower side of the nipple, persistent and unrelieved, you need to seek medical treatment.