Side sleeping chest pain may be caused by cardiogenic factors, chest trauma, sleeping on the side for too long, pleural effusion, costochondritis and other factors. 1. Cardiogenic factors: cardiogenic factors such as myocarditis, coronary heart disease, etc., because of myocardial injury, myocardial ischemia, the heart appears to be a burst of throbbing pain, so when sleeping on the side of the chest pain phenomenon will occur. 2. Chest trauma: when the chest is injured by direct or indirect violence, it will lead to damage to the sternum and ribs, and sleeping on the side is easy to aggravate the condition, and chest pain will occur, and it is recommended that patients with a recent history of clear trauma go to the hospital for further examination. 3. Sleeping on the side for too long: sleeping on the side for too long will cause the lower part of the chest wall to be compressed, which will cause the blood circulation of the local muscle tissues to be abnormal, resulting in chest pain. 4. Pleural effusion: Tumor, inflammation and other factors may induce pleural effusion, and when sleeping on the side, the effusion will flow with the change of position, thus stimulating the pleural nerve and causing chest pain. 5. Costal chondritis: Costal chondritis often occurs in the 2nd to 4th rib cartilage next to the sternum, which will cause localized pain, especially when the pain is aggravated by turning over, deep breathing and coughing. It is recommended that the patient go to the hospital, the doctor will be based on clinical symptoms and test results to give the appropriate diagnosis, identify the cause of the disease, timely treatment.