Stabbing pain in the left side of the chest may be caused by cardiac neurosis, costochondritis, angina pectoris and other diseases. 1. Cardiac neurosis: the cause of this disease is not clear, it may be related to heredity, excessive depression, introversion and life stress, tension and other environmental factors. Typical symptoms are palpitations (accelerated heartbeat, often accompanied by panic), pins and needles pain in the precordial region, chest tightness, etc. Therefore, the patients will have the manifestation of stabbing pain in the left side of the chest. 2. Costochondritis: Research shows that the occurrence of this disease is related to viral infection, nutritional disorder of costal cartilage, chronic strain of costal joint ligaments, violent impact and other reasons. Patients will have symptoms such as chest tightness and chest pain, which can be manifested as stabbing pain on the left side of the chest. 3. Angina pectoris: due to insufficient blood supply to the coronary arteries, myocardial acute temporary ischemia and hypoxia caused by episodes of chest pain or chest discomfort, which can be manifested as left-sided chest pain symptoms. In addition, the left side of the chest pain should also be considered to be breast hyperplasia, pneumothorax and other diseases. It is recommended that patients with left sided chest pain go to the hospital to get a clear picture of the cause of the pain.