Left subcostal pain can be categorized into physiological and pathological, and pathological causes include chest wall diseases, digestive system diseases and respiratory system diseases. 1. Physiological factors: if there are intense emotions such as anger and anxiety, it may cause obstruction of blood circulation, which may lead to left subcostal pain; if the exercise is more intense, which may lead to the phenomenon of gas, it may also be manifested as left subcostal pain. 2. Pathological factors (1) Chest wall diseases: if you suffer from chest wall diseases such as rib fracture and costochondritis, it will cause this symptom. (2) Diseases of the digestive system: such as gastritis, gastric ulcer, pancreatitis and gastric cancer can cause this symptom because the stomach and pancreas are located under the left side of the ribs. (3) Respiratory diseases: Respiratory diseases such as left-sided pneumonia, emphysema and lung abscess can also cause this symptom. If you suspect that this symptom is pathologic, it is recommended that you go to the hospital in time.