Chest pain is a common and life-threatening condition caused by lesions of the chest wall, cardiovascular, respiratory system and abdominal cavity that stimulate the intercostal nerve, phrenic nerve, posterior spinal nerve root, sympathetic nerve innervating the heart and aorta and vagus nerve innervating the trachea, bronchus and esophagus. Since the pain threshold of each person is different, the location and severity of chest pain do not necessarily parallel the condition. If the cause of chest pain is complex and diverse, such as superficial or minor local damage to the chest wall, it is easy to diagnose and manage, but if the cause is visceral (such as angina pectoris, myocardial infarction, pulmonary infarction, arterial entrapment), the lesion is often hidden and can be life-threatening if not diagnosed and managed in time. Common causes of clinically induced chest pain include: inflammation, trauma, tumor infiltration, chemical stimulation of the viscera, ischemia and hypoxia, distension, smooth muscle spasm, mechanical compression or stimulation, etc. In addition, visceral lesions can also produce referred pain in addition to local pain. Tumor infiltration is a common cause of chest pain. Clinically common tumors such as bronchial lung cancer, mediastinal tumors, rib and rib cartilage tumors, pleural tumors, esophageal cancer, liver cancer, intercostal nerve tumors, thoracic spinal cord and intraspinal tumors, acute leukemia, etc. Due to the infiltration of cancer cells or compression of tumor tissue, the chest wall, cardiovascular system, respiratory system and abdominal organs are damaged, and the damaged tissues release K+, H+, histamine, 5-hydroxytryptamine, bradykinin, substance P and prostaglandin, which act on the sensory nerve endings of trachea, bronchus, esophagus, heart and aorta innervated by intercostal nerve, phrenic nerve, posterior spinal nerve root and vagus nerve, causing chest pain. The result is chest pain. In addition to tumor infiltration, the following diseases may cause chest pain: Inflammatory lesions (1) inflammation of chest wall: herpes zoster, epidemic chest pain, subcutaneous cellulitis, dermatomyositis, costochondritis, intercostal neuritis, periarthritis of shoulder joint, tuberculous thoracic spondylitis, osteomyelitis, etc. (2) Infections of internal organs: pleurisy, pneumonia, tuberculosis, bronchitis, pericarditis, mediastinitis, esophagitis, pancreatitis, cholecystitis, and subdiaphragmatic abscess. Ischemic and hypoxic cardiopulmonary diseases: angina pectoris, myocardial infarction, pulmonary infarction, hypertrophic cardiomyopathy, cardiac valvular disease, entrapment aneurysm, etc. Mechanical compression, infiltration: chest pain caused by expansion and compression of primary or metastatic tumors in the thoracic cavity, erosion of the sternum by aortic aneurysms, expansion of the outer membrane of aortic coarctation aneurysms, hypertrophic spondylitis with hyperplasia, compression of posterior spinal nerve roots by bone warts, and stimulation by foreign bodies in the trachea and esophagus. Chemical irritation: tracheitis and bronchitis caused by inhalation of irritant gases, esophagitis caused by taking corrosive agents. Trauma: various injuries of chest wall or chest organs. Phytonadic dysfunction: chest pain caused by hyperventilation syndrome, cardiac neurosis, cardia spasm, etc. Reflex or involvement pain: shoulder joint and its peripheral inflammation often accompanied by chest pain, cervical rib and anterior oblique muscle lesions cause upper chest and axillary chest pain, angina pectoris causes posterior, middle and upper sternal pain, but also left shoulder and medial forearm skin pain, subdiaphragmatic lesions such as hepatocellular carcinoma, liver abscess, subdiaphragmatic abscess, biliary tract disease, splenic flexure syndrome, splenic infarction cause lower chest pain, epigastric pain and radiation to the back.