If you smoke a lot of cigarettes and have a vague pain in the middle of your chest, it is mainly considered to be related to respiratory system diseases, digestive system diseases, heart diseases and other diseases. 1. Respiratory diseases: Long-term heavy smoking will cause certain damage to the respiratory system, inducing pneumonia, emphysema, chronic pharyngitis and other diseases, which will lead to the symptom of hidden pain in the middle of the chest. 2. Digestive system diseases: long-term smoking may also lead to cardia muscle relaxation, triggering reflux esophagitis and other diseases, resulting in vague pain in the chest. In addition, you should also consider the possibility of other digestive system diseases such as gastric ulcer and chronic gastritis, which can also trigger this condition. 3. Heart disease: diseases such as angina pectoris and coronary heart disease can lead to symptoms of chest pain in some patients. 4. Other diseases: such as pleurisy, external injuries, etc., which can also trigger this syndrome. The cause of this symptom is complex. It is recommended to seek medical examination as soon as possible, after clarifying the cause of the disease, follow the doctor’s instructions for treatment.