Hidden pain at the lower end of the left sternum may be caused by costochondritis, coronary heart disease, pleurisy, and other causes such as gastric ulcer. 1. Costal chondritis: the etiology of costal chondritis is still unclear, and it is considered to be related to viral infection, endocrine abnormality, thoracic and rib joint ligament strain, bacterial blood-borne infection, trauma and other factors. Patients will have anterior chest pain, back radiating pain, if the patient’s left side of the ribs with costochondritis, there will be a hidden pain in the lower end of the left sternum. 2. Coronary heart disease: Coronary heart disease is caused by the accumulation of plaque in the walls of coronary arteries, which makes the blood supply to the heart insufficient, and the patients will have pain in the middle or left side of the chest easily. Therefore, patients with coronary artery disease will have the symptom of hidden pain at the lower end of the left sternum. 3. Pleurisy: Pleurisy is considered to be caused by autoimmune diseases, malignant tumors, bacterial or fungal infections and other factors. Patients will show chest pain, chest tightness, cough, sputum and so on, so patients may have the manifestation of hidden pain in the lower part of the left sternum. 4. Other: patients appear left sternum lower hidden pain is also considered to be gastric ulcer, pulmonary embolism, bone fracture, periostitis and other causes. It is recommended that patients need to consult a doctor in a timely manner when they have left lower sternal recessive pain, and the doctor will choose the appropriate measures for treatment after clarifying the cause of the disease.