Left upper back pain may have the following reasons: first, herpes zoster, in the early stage of herpes zoster can appear back pain, in the incubation period of 1-2 weeks later, herpes can appear in clusters, this time to the dermatology department for diagnosis and treatment; second, intercostal neuralgia, intercostal neuralgia patients can appear in the back of the inter-costal nerve course of the pain, often hidden pain, tingling or radiating pain, this time to carry out relevant investigations, if necessary, trophic nerve and closed treatment; third, rib disease, when the ribs appear tumor or metastatic tumor, it can appear in the left upper back pain. At this time, relevant physical examination should be carried out, and if necessary, nutritional nerve and closed treatment should be carried out; thirdly, rib disease, when there is a tumor or metastatic tumor in the rib cage, the pain in the upper left back can occur, and CT examination should be carried out for diagnosis at this time; fourthly, cardiac disease, when there is an infarction or angina pectoris, the pain in the upper left back can occur radically, and at this time cardiac imaging or ECG examination, blood tests, blood tests, and so on should be carried out; fourthly, cardiac disease, when there is an infarction or angina, the pain in the upper left back will occur radially. Fourth, heart disease, when heart infarction or angina pectoris occurs, the pain in the upper left back will be radiating, and then cardiac imaging or electrocardiography or blood test should be conducted for diagnosis; fifth, lung disease, when there are tumors or inflammation in lungs, the pain in the upper left back can also occur, and then CT examination of lungs should be conducted for diagnosis.