Left chest pain is mostly considered as heart disease, lung disease, breast disease, trauma, etc. Electrocardiogram, cardiac ultrasound, breast ultrasound, chest X-ray and chest CT and other related examinations are needed. 1. Electrocardiogram and cardiac ultrasound: Electrocardiogram and cardiac ultrasound can check whether there is myocardial infarction, angina pectoris and other heart diseases. Some heart diseases are accompanied by chest tightness and fatigue. 2. Breast ultrasound: check whether there are breast hyperplasia, mastitis, breast nodules or breast tumors and other diseases. For example, breast hyperplasia can be manifested as chest pain associated with menstrual cycle. 3. Chest radiograph and chest CT: it can check whether there is pneumonia, pneumothorax, lung mass, chest wall, mediastinum and other diseases, lung diseases can be accompanied by cough, sputum, hemoptysis, chest tightness and other manifestations in addition to chest pain. There are other diseases that cause left chest pain, and it is recommended that patients go to the hospital in time to avoid delaying their condition.