Left-sided chest pain can be caused by physiological and pathological factors, and the pathological causes include cardiovascular diseases, respiratory diseases and chest wall diseases. 1. Physiological factors: if you are overworked or keep a certain position for a long period of time, it may lead to the feeling of tightness and pain, which is a normal physiological phenomenon and can be recovered after resting without special treatment. 2. Cardiovascular disease: the left side of the chest is in the position of the heart, if you suffer from myocarditis, coronary heart disease and hypertension and other diseases, will be due to cardiac discomfort leading to boring pain symptoms. 3. Respiratory diseases: the left side of the chest is also the location of the left side of the lungs, so the stuffy pain may be suffering from asthma, left side of the pneumonia or bronchial dilatation and other respiratory diseases. 4. Chest wall diseases: left rib fracture, costochondritis, intercostal neuralgia and other chest wall diseases can also lead to the left side of the chest boring pain symptoms. After excluding physiological factors, it is recommended to go to the hospital in time for further examination to clarify the cause of the disease and standardize the diagnosis and treatment.