There are many reasons for the vague pain above the left side of the chest, such as physiological factors, costochondritis, lung disease, coronary atherosclerotic heart disease and so on. 1. Physiological factors: patients lifting heavy objects for a long time, or expanding the chest exercise, may lead to local muscle lactic acid accumulation, which leads to the phenomenon of vague pain in the left side of the upper chest. 2. Costal chondritis: Costal chondritis can cause vague pain above the left side of the chest, which may be related to the long-term chronic strain of the thoracic rib joint ligaments, viral infections and other factors. 3. Lung diseases: such as pneumonia, tuberculosis, lung cancer and other diseases, can also lead to vague pain on the left side of the chest, usually accompanied by coughing, coughing up sputum and other phenomena. 4. Coronary atherosclerotic heart disease: atherosclerosis of the coronary arteries supplying the heart, narrowing the lumen of the coronary arteries, insufficient blood supply to the coronary arteries triggers angina, which can be characterized by a vague pain in the upper left side of the chest. Causes of the left side of the chest above the hidden pain is very many reasons, it is recommended that patients go to the hospital in a timely manner for examination, to identify the cause of the standardized treatment, do not ignore the symptoms, delay the condition, so as not to delay the condition.