I. Mechanism of chest pain occurrence Any physical, chemical, mechanical and biological stimuli, such as mechanical compression, chemical stimulation, trauma, inflammation, tumor stimulation of sensory fibers of large blood vessels of the heart, vagal sensory fibers of trachea, bronchus and esophagus, and afferent fibers of phrenic nerve, can cause the sensation of chest pain. In addition, afferent impulses from the viscera can also cause pain sensation in the corresponding parts of the body surface due to the mechanism of pulling pain. Stimulation of afferent nerves by substances such as local lactic acid in myocardial ischemia can cause pain sensation in the jaw, left shoulder of the neck, and left arm. The lesions or injuries of all layers of the chest wall (skin, muscles, intercostal nerves, ribs, sternum, thoracic vertebrae up to the pleural wall layer), heart, aorta, pulmonary artery, trachea, esophagus, mediastinum and lung can cause chest pain. Therefore, chest pain is a multi-cause symptom. There are many causes of non-traumatic chest pain, including neuropathy such as herpes zoster before rash, intercostal neuritis, thoracic medullary compression, thoracic radicular pain and bone lesions such as costochondritis and thoracic spinal tuberculosis; thoracic organ lesions such as angina pectoris, myocardial infarction, coronary aneurysm, idiopathic obstructive cardiomyopathy, heart valve disease, certain congenital heart diseases, aortic sinus aneurysm, aortic coarctation, pulmonary embolism The primary pulmonary hypertension, pneumothorax, pleurisy, thoracic outlet syndrome; diaphragmatic hernia and other organ lesions in the mediastinum such as esophagitis, esophageal cancer, gastric esophageal reflux, esophageal diverticulum, cardia incontinence, etc. can cause chest pain. The main non-traumatic causes of chest pain: myocardial lesions: stable angina pectoris, acute coronary syndrome (ACS), obstructive cardiomyopathy, myocarditis pericardial lesions: pericarditis. Cardiac valve lesions: aortic stenosis, subaortic stenosis, mitral valve prolapse Vascular lesions: aortic coarctation, pulmonary embolism, pulmonary hypertension Pulmonary and tracheal lesions: pulmonary infection, inflammation, infiltration, pneumothorax, mediastinal pneumothorax, tracheobronchitis. Bone and muscle lesions: costochondritis, intercostal muscle strain, cervical and thoracic spine lesions Digestive system lesions: esophageal reflux/spasm, esophageal mucosal tear, cholelithiasis, dyspepsia, pancreatitis Other causes: herpes zoster, chest wall tumors