Cancer-related diseases associated with left shoulder pain include lung and liver cancer, scapula tumors, and other diseases. However, it is not always caused by cancer, but may also be caused by cold and frozen shoulder. 1. Lung cancer and liver cancer: tumors occurring at the tip of the lung can cause left shoulder pain, meanwhile, hepatobiliary epithelial cell carcinoma and primary liver cancer can also cause radiating pain in the shoulder area. When shoulder pain occurs in patients with malignant tumors, the symptoms are relieved by activity because the pain is fixed and immobile. Generally, it is necessary to check the cancer further through examination to find occupying lesions in lungs and liver. 2. Scapular tumor: left shoulder blade pain may be caused by primary bone tumor and secondary bone tumor. The larger the tumor is, the stronger the pressure on local tissues, and it will also cause left shoulder blade pain. Once detected, it should be treated early, through surgery, radiotherapy and chemotherapy. Patients with left shoulder blade soreness are recommended to go to the hospital for timely examination and standardized treatment under the guidance of doctors. Usually pay attention to keep warm, appropriate exercise, and eat a light diet.