Chest pain is a common clinical symptom with many causes, and the location and severity of chest pain do not necessarily correspond to the location and severity of the lesion. Trauma, inflammation, tumor and certain physical and chemical factors that cause tissue damage to the intercostal nerve, phrenic nerve, posterior spinal nerve roots and vagus nerve can all cause chest pain when the nerve endings in the esophagus, bronchi, lungs, pleura, heart and aorta are stimulated. The identification can be done by first analyzing which major category it belongs to, and then identifying each cause in this major category. 1, the site of chest pain chest wall skin inflammation in the affected area of the skin appears red, swollen, hot, painful and other changes. Herpes zoster is a cluster of small blisters that are distributed along the nerves and do not cross the midline, with obvious pain. In epidemic myalgia, there may be severe pain in the chest and abdominal muscles, which may radiate to the shoulders and neck. Non-suppurative myochondritis mostly invades the 1st and 2nd rib cartilage, and the affected area is elevated and painful, but the skin is mostly free of redness and swelling. The pain of angina pectoris and acute myocardial infarction is often located in the retrosternal or precordial region. The pain of esophageal disorders, diaphragmatic hernia, and mediastinal tumors is also located in the posterior sternum. Spontaneous pneumothorax, acute pleurisy, and pulmonary infarction often present with severe chest pain on the affected side. Blood disorders cause sternal pain. History of previous chest trauma and painful inspiration during weather changes. The first task in evaluating chest pain is to distinguish between chest pain of the respiratory system or chest pain related to other systems, which is not always easy. The nature of the pain and the setting in which it occurs can often be used to distinguish pain from angina pectoris or myocardial infarction; it may be more difficult to identify pain due to an interstitial wall aneurysm based solely on the medical history. 2. Nature of chest pain Intercostal neuralgia is a paroxysmal burning or stabbing pain. Myalgia is often sore. Bone pain is sore or cone pain. Esophagitis and diaphragmatic hernia often present burning pain or burning sensation. Angina pectoris is often crushing pain and may be accompanied by a feeling of suffocation. Aortic aneurysm with chest wall erosion is cone pain. Primary lung cancer and mediastinal tumor may have chest pain. 3.Factors affecting chest pain Angina pectoris is often triggered by exertion or mental tension, and is paroxysmal, and is rapidly relieved by taking glycerine nitrite tablets. Myocardial infarction often presents persistent severe pain, which is not relieved by taking glyceryl nitrite tablets. Chest pain due to cardiac neurosis is often improved by exercise. In pleurisy, spontaneous pneumothorax, and pericarditis, chest pain is often aggravated by coughing or deep breathing. In hyperventilation syndrome, chest pain can be relieved by using a paper bag to breathe back in and out. Chest pain accompanied by the following symptoms is suggestive of diagnosis: 1. with cough, commonly in tracheal and bronchial pleural diseases; 2. with dysphagia, commonly in esophageal diseases; 3. with hemoptysis, commonly in tuberculosis, pulmonary infarction, primary lung cancer; 4. with dyspnea, commonly in lobar pneumonia, spontaneous pneumothorax, exudative pleurisy, hyperventilation syndrome, etc.; 5. angina pectoris, myocardial infarction often develops in Hypertension, atherosclerosis on the basis of. Cause pathology 1, inflammation: dermatitis, nonsuppurative costochondritis, herpes zoster, myositis, epidemic myalgia, pleurisy, pericarditis, mediastinitis, esophagitis, etc.; 2, visceral ischemia: angina pectoris, acute myocardial infarction, cardiomyopathy, pulmonary infarction, etc.; 3, tumor: compression or infiltration of primary lung cancer, mediastinal tumor, myeloma, leukemia, etc.; 4, other causes: spontaneous pneumothorax, thoracic aortic aneurysm, sandwich aneurysm, hyperventilation syndrome, trauma, etc.; 5, cardiac neurosis.