Painful rotator cuff injury with effusion may be caused by inflammation after the injury, which can be treated with diclofenac sodium for pain relief, extraction of effusion, shoulder arthroscopy and other treatments. 1. Drug treatment: rotator cuff injury with fluid accumulation is often accompanied by severe pain, activity limitation and other symptoms, diclofenac sodium, ibuprofen and other non-steroidal anti-inflammatory drugs can be used to relieve pain and inflammation. Severe cases can also be cohabited with local injection of lidocaine hydrochloride and compound betamethasone closure therapy, closure therapy may appear allergic reactions and other side effects. 2. Extraction of fluid: If the amount of fluid in the joint cavity after rotator cuff injury is large, the extraction of fluid in the joint cavity can be considered, and bandaging and compression should be carried out after extraction. Fluid extraction is a puncture treatment, which may have the risk of infection and recurrence of the fluid. 3. Arthroscopic surgery: If the rotator cuff is severely torn, arthroscopic repair of the damaged rotator cuff can be considered to restore muscle strength and maintain joint function. In the event of rotator cuff injury pain with effusion, it is recommended to go to the regular hospital in time, according to the patient’s condition, choose the appropriate treatment, do not blindly use drugs.