Hidden pain in the left chest of men may be caused by soft tissue injury, pneumonia, coronary heart disease and other reasons. 1. Soft tissue injury: if the chest is traumatized or collided, the local soft tissue will be damaged, resulting in pain and swelling in the patient’s left chest. 2. Pneumonia: If the patient smokes for a long time or the lungs are infected by bacteria or viruses, it is easy to trigger pneumonia, resulting in coughing, coughing up sputum, chest pain, dyspnea and other symptoms, causing the patient to show a vague pain in the left chest. 3. Coronary heart disease: if the patient suffers from coronary heart disease, it will lead to angina pectoris, which will cause the patient to have the symptom of vague pain in the left chest. It is recommended to go to the regular hospital to do chest CT or MRI and other related examinations to clarify the cause of the disease, and treatment under the advice of the doctor.