The causes of pain in old wounds usually include local inflammation of old wounds, new infections, overgrowth of scar tissue, and foreign objects. 1. Local inflammation: some old wounds are deeper, resulting in damage to the soft tissues and fascia inside, and the lack of recovery at the end of the injury leads to local aseptic inflammation, thus causing pain in the old wound. 2. The occurrence of new infections: some infections are manifested as delayed infection, the old wound bacterial infection, inflammation will stimulate the sensory nerve endings, thus causing the old wound pain. 3. Excessive proliferation of scar tissue: the injured nerves of old wounds are not fully recovered, resulting in poor blood circulation, when the weather is cold or strenuous exercise, so that the nerve endings are severely stimulated will cause pain in old wounds. 4. Foreign body: If there is a foreign body inside the wound, such as suture thread, there will usually be pain, redness and swelling. If it is found that there may be other foreign bodies in the wound, ultrasonography or x-ray examination can be carried out to determine the nature and location of the foreign body and remove it as soon as possible. It is recommended that patients go to the hospital in time to consult the doctor, to clarify the cause of the disease and then under the guidance of the doctor active treatment.