The causes of vague pain under the left rib cage in the back are as follows: First, lung infection, which can occur when the pleura or pleural infection is close to the left side, patients are often accompanied by cough, coughing, chest pain, fever and other symptoms, a CT examination of the chest can clarify the diagnosis, after giving anti-infection and symptomatic treatment, the symptoms can gradually improve. Second, it appears after strenuous activities, and those with mild symptoms usually do not need special treatment. After paying attention to rest, the symptoms will gradually improve. If the symptoms do not ease after rest or gradually worsen, and discomfort manifestations such as panic and chest tightness appear, you should go to the hospital promptly. Third, shingles, early patients can appear, pay attention to the presence of herpes on the skin, typical symptoms and signs can generally be clearly diagnosed. Fourth, heart disease, such as acute angina pectoris, acute myocardial infarction patients can appear, patients in addition to the above symptoms, but also accompanied by panic, chest tightness, pain in the precordial region, pain in the back of the shoulder, etc., to perform electrocardiography, echocardiography, heart attack three examinations can be clearly diagnosed. V. Trauma, advanced tumor, etc. can also be caused, which should be paid attention to, and timely visit the hospital to avoid delaying the disease.