There are several possible causes of vague pain under the left side of the ribs: first, intercostal neuralgia, which is relatively common, often located at the edge of the ribs, the nature of the hidden pain, usually paroxysmal, when the patient has fatigue, poor sleep, immune deficiency will easily appear, there may be local pressure pain when pressing the local; second, rib or chest wall muscle tissue injury, usually caused by trauma or pulling, etc., can The second, rib or chest wall muscle tissue injury, usually caused by trauma or pulling, can be improved by chest X-ray or chest CT examination to clarify whether there is rib injury or fracture, soft tissue injury has diffuse local pressure pain, topical futalin ointment can help relieve the pain caused by soft tissue, patients with rib fracture need to go to the orthopedic department for further consultation; third, lung lesions or pleural lesions, this pain is generally related to respiratory action, the pain will increase when the patient inhales deeply or exhales deeply. The improvement of chest CT examination can help diagnose and, if necessary, thoracentesis is needed to further clarify whether there is any lesion in the pleura.