Breast pain during breastfeeding may be caused by bacterial infection, milk stagnation, milk duct spasm and other causes. 1. Bacterial infection, when the breast is damaged or the nipple is cracked, the bacteria can be retrograde infection, forming inflammation or even purulent infection, which can often lead to pain. After bacterial culture and drug sensitivity test, antibiotics will be used to treat the symptoms. 2. Breast milk stagnation, breastfeeding women often due to excessive milk secretion, poor discharge of milk ducts, resulting in breast milk stagnation and pain. The pain is usually relieved by applying hot compresses to the breasts, localized breast massage, and sucking out the stagnant milk with a breast pump. Prolonged milk stagnation may lead to bacterial infection. 3. Breast duct spasm, when the breast duct spasm, the milk is not discharged smoothly, will also cause pain. In addition, breast hyperplasia, breast trauma, and breast cancer may also produce similar clinical manifestations. It should be noted that when breast pain is present, one should go to the hospital in time for examination and treatment under the guidance of the doctor.