Patients who have pain during inspiration on the left side of the chest: 1. High-risk chest pain must be considered, such as acute coronary syndrome, aortic coarctation, pulmonary embolism, and tension pneumothorax, all of which will have obvious and severe chest pain during inspiration on the left side. However, the incidence of this disease is relatively low, the mortality rate is high, and the pain is very intense with strong pulling-like and tearing-like pain, which must reach the hospital quickly and timely for consultation.2. For some non-high-risk chest pain, often in coronary artery disease, angina pectoris, acute myocarditis, pericarditis, and pericardial compression have the above symptoms.3. Respiratory diseases, such as large left-sided pleural effusion, lung infection, and 4.If the left sternum or ribs are fractured by trauma, or if there are contusions in the surrounding soft tissues, the above symptoms will also occur.