If a patient has breast pain after breastfeeding, consider the following reasons: 1. Consider mastitis, because the ducts of the breast go straight to the nipple, and if the nipple is not cleaned up in time, there will be bacterial infection, and the bacteria will infect the mammary gland retrograde upwards, or because the excess milk is not breastfed in time, or sucked out with a breast pump. 2. Consider that the patient has breast nodules, and the patient’s breast gland changes as the estrogen level in the body rises and falls. 3. Consider that the patient has localized occupying lesions in the breast, including benign and malignant lesions, benign lesions include cysts, fibroids, etc., and malignant lesions include breast cancer, etc., which may cause stabbing pain due to pressure on the nerve.