Whether the pain in the back of the left shoulder is an early sign of cancer or not is objectively analyzed according to the different causes and nature of the pain: a. If the pain in the back of the left shoulder is caused by frozen shoulder, it is not an early sign of cancer. Patients can improve the blood circulation of the back of the left shoulder through local heat physiotherapy and functional exercise to relieve the pain symptoms caused by frozen shoulder, and the prognosis of patients is better. Second, patients with acute pancreatitis can be accompanied by large amount of pancreatic fluid exudation, causing serious infection in the abdominal cavity, which manifests as painful symptoms in the back of the left shoulder. This condition is not an early sign of cancer, and can be treated by active anti-infection, inhibition of pancreatic fluid secretion and appropriate rehydration, and the pain symptoms in the back of the left shoulder can be gradually relieved. Patients with coronary atherosclerotic heart disease and sudden onset of myocardial ischemia and hypoxia can also manifest as radioactive pain in the back of the left shoulder, which is caused by coronary heart disease and is not an early sign of cancer.