The cause of rib pain under the chest is mainly the lower chest and upper abdominal tissue organ lesions involving pain, and a small part of the lower chest rib itself. 1. Lower chest and upper abdominal tissues and organs lesions involving pain: (1) Chest diseases, such as: chest wall trauma, lung infection, lung cancer, pleurisy, intercostal neuritis of the lower chest wall and other chest diseases can be involved in the periosteum of the rib cage or pleural tissues to cause rib cage entrapment pain. (2) Upper abdominal diseases such as gastritis, gastric ulcer, splenomegaly, hepatitis, hepatocellular carcinoma, cholecystitis, etc. can also cause rib retraction pain in the lower chest. 2. lesions of lower chest rib itself: rib fracture, costochondritis, rib tumor and other rib diseases can cause rib pain below chest. Rib pain under the chest, severe pain or long-term pain can not be relieved, it is recommended to go to the hospital for further diagnosis and treatment.