A vague pain over the left chest may be the result of coronary artery disease, cardiogenic angina, and pleurisy. 1. Coronary heart disease: Due to atherosclerosis involving the coronary arteries, the blood supply and oxygen supply to the heart are affected, resulting in insufficient blood supply to the heart muscle. If the blood supply to the heart muscle is insufficient, it will trigger the symptoms of vague pain in the chest. 2. Angina of cardiac origin: most of them are squeezing or oppressive pain, and all of them are attacked after exercise or when emotionally excited, and the duration is short, which can be relieved after resting for a few moments. 3. Pleurisy: Pleurisy is a disease caused by inflammation of pleural tissue or other diseases invading the pleura. The most common symptoms of pleurisy are chest pain, chest tightness, and in some patients, coughing and sputum. When the patient has the symptom of vague pain in the chest, the patient should go to the hospital in time for diagnosis and choose targeted treatment.