Left subcostal pain may be related to left-sided costochondritis, bone fracture, angina, respiratory diseases, gastroduodenal diseases, etc. 1. Left costochondritis: chronic non-specific inflammation in the left costochondral area, which can show hidden pain in the costochondral area, and may also radiate pain to the back of the shoulder, and excessive exercise will aggravate the pain symptoms. 2. Fracture: Fracture of the left side of the ribs under the impact of external forces can also cause pain symptoms, which need to be clarified by radiographs. 3. Angina pectoris: usually after overexertion, emotional excitement and satiety. Because of myocardial ischemia, hypoxia, chest tightness, chest pain, shortness of breath and other symptoms, can be manifested as the left side of the subcostal pain, can be gradually relieved after resting or taking nitroglycerin. 4. Respiratory diseases: such as left-sided large-scale pneumonia, pleurisy, pulmonary herpes, etc., because of inflammatory stimulation, nerve irritation, etc., there will be left-sided subcostal pain and discomfort, often accompanied by coughing, coughing up sputum, fever and other symptoms. 5. Gastroduodenal diseases: such as gastroduodenal ulcer, gastritis, etc., due to nerve involvement pain, there will also be hidden pain under the left rib discomfort, often accompanied by nausea, acid reflux, belching (belching) and other symptoms. It is recommended that patients with left subcostal pain should go to the hospital in time to find out the cause of the pain and be treated under the guidance of the doctor.