Breast-conserving surgery is actually a local enlargement of the tumor resection, which leads to pain because:1. The original breast cancer lesion is only 2cm, and the diameter of resection may be 4cm, or even larger, and the local trauma is one of the causes of postoperative pain; 2. In order to maintain a good postoperative appearance in some patients, the local suture will be deformed after resection, and then plastic surgery techniques may be adopted, such as residual glandular tissue The displacement after freeing can also cause more trauma. The greater the trauma, the greater the likelihood of postoperative pain; 3. Radiotherapy is needed after breast-conserving surgery, and the purpose of radiotherapy is to kill the cancer cells that may remain. The effect of radiotherapy is to reduce the activity of localized tissues by irradiating them with rays. So this part can also cause pain in the patient. This is a subjective feeling and may be felt differently by different people.