Rib pain on the left side of the chest on pressure may be caused by rib fracture, chest wall inflammation, malignant tumor infiltration of the ribs and so on. 1. Rib fracture: rib fracture is often caused by external force, manifested as chest pain, bone rubbing sound (feeling), and obvious pain on pressure. Chest radiograph or chest ct can make a clear diagnosis. 2. Inflammation of chest wall: such as costochondritis, costochondritis, chest wall soft tissue inflammation, intercostal neuritis and other diseases, there can be pain in the ribs when pressed. Costochondritis, chest wall soft tissue inflammation can appear local redness, swelling, heat, pain; intercostal neuritis manifested as pain along the direction of rib travel strip area, press the back pain can be involved in the chest. 3. Malignant tumor infiltrating ribs: in the advanced stage of malignant tumor, the tumor invades the left side of the ribs, and the left side of the ribs may have pain on pressure, accompanied by cough, hemoptysis, emaciation and other symptoms. The left side rib pressure pain should be analyzed together with other symptoms, and it is recommended to consult the hospital in time, supplemented by appropriate physical examination, so as not to miss the diagnosis or misdiagnosis.