There are more reasons for pain in the left back. Usually, pain can be caused directly by lesions in the painful area or by trauma or surgery, while damage to adjacent parts or other systemic lesions can also cause radiating pain to the left back. 1, cardiovascular disease: myocardial infarction, angina pectoris due to coronary artery disease, such diseases are mainly chest pain, but can radiate to the left back; 2, vertebral lesions: including thoracic scoliosis deformity, thoracic disc herniation, thoracic vertebral osteophytes, age-related spinal osteoarthritis, ankylosing spondylitis, thoracic spinal tuberculosis, thoracic rib joint misalignment and other diseases can appear in the left back or even the entire back pain. Such diseases are often accompanied by soreness and swelling, cramping and pain in the back of the shoulder, as well as numbness and weakness of the limbs; 3. Respiratory diseases: pneumonia, pleural adhesions, lung cancer, etc. can damage the intercostal nerves and cause radiological pain to the left back; 4. Liver, biliary and gastric diseases: mainly including biliary colic, pancreatitis, gastric and duodenal tumors, etc., which can also cause radiological pain to the left back; 5. Surgical trauma: such as rib fracture reset, Breast cancer resection, lung cancer resection, etc., the surgical site can cause pain after being stretched; 6, physical or chemical damage: harmful drugs such as chlorpromazine, amiodarone, etc., may cause nerve damage when used improperly. Radiation damage (X-ray, radium, cobalt irradiation) and other factors acting on the left back can also cause pain; 7, tumors: multiple, multi-system tumor diseases, such as bone tumors can metastasize to the scapula and cause pain; 8, other: left back muscle strain, cold, sprains, etc., can cause pain.