When a similar situation occurs, the patient should first determine whether it is caused by trauma, whether the local breast tissue has been recently squeezed, and whether there is any obvious redness or swelling of the local skin. Mastitis, which is the most important cause of breast pain during lactation. Patients who have difficulty determining this on their own need to go to the hospital, preferably to a breast surgeon, usually for ultrasound and routine blood tests, etc. If mastitis has occurred, patients are advised to have it treated as soon as possible and it may affect the baby’s breastfeeding in the near future, usually the earlier it is detected the better the results.