The sudden appearance of chest pain, to consider the heart and lung two systems of disease, if the patient for the dull feeling in the chest, to consider whether it is angina pectoris. If the patient’s pain is related to breathing, especially the pain is stimulated by deep breathing, such people should rule out myocardial ischemia and also rule out whether they have lung-related diseases, mainly including the following: i. Pneumothorax, pneumothorax people who undergo X-ray examination can find compression of the lungs. Second, lobar pneumonia, such people have a history of pre-cold, incorrect medication history, if the chest CT examination can see the symptoms of lobar pneumonia. Pulmonary embolism, such people will have chest pain, dyspnea, if the blood gas analysis examination will find that the oxygen content of the body decreased, carbon dioxide content increased, the pulmonary artery CTA examination can be found in the pulmonary artery embolism.