In men, vague pain in the left chest can have the following causes depending on age and medical history: 1. Diseases of the chest wall, such as herpes zoster, epidemic chest pain, myositis, and costal neuritis. 2. Angina pectoris, such as acute heart attack, myocarditis, and acute pericarditis. 3. Diseases of the respiratory system, such as pleurisy, tumors of the pleura, pneumothorax, and pneumonia. 4. Diseases of the mediastinum, such as mediastinitis and mediastinal tumors. 5, Others such as subdiaphragmatic liver abscess, splenic infarction. All of these can cause vague pain, mainly depending on the severity, but not to go to the hospital to do electrocardiogram for further examination.