Left shoulder blade pain is not necessarily a sign of serious illness, it may be a manifestation of frozen shoulder, rotator cuff injury, cervical disc protrusion and other diseases, or it may be a case of heart attack, lung disease and other conditions. 1. Frozen shoulder: due to cold stimulation or long-term chronic strain, inflammatory reaction occurs in the tissues and structures around the shoulder joint during activities, resulting in edema and oozing changes, which will affect the blood circulation of the scapula, leading to pain, swelling and other symptoms. 2. Rotator cuff injury: strenuous exercise without adequate preparation before exercise, or incorrect exercise posture will lead to damage to the rotator cuff structure, so that the surrounding muscles, ligaments, nerves and other inflammation occurs, thus causing scapular pain symptoms. 3. Cervical disc herniation: working with head down for a long time will easily lead to degenerative changes of cervical intervertebral discs, resulting in the discs protruding backward and compressing the surrounding nerves, making the innervated area have abnormal sensation, which in turn will cause pain and numbness. 4. Heart attack: When heart attack occurs, it will be manifested as pain in the precordial area, anterior to the sternal handle and scapular area, accompanied by chest pain, chest tightness, dyspnea, and a sense of dying. 5. Lung disease: when inflammation occurs in the lungs, if the lesion site is close to the upper lung, it will show scapular pain, and there will be fever, cough, sputum, chest pain and other manifestations. If it is a lung tumor, it may cause pain in the left scapular region, and there will be hemoptysis and blood in sputum. In order to relieve the symptoms of scapular pain, it is recommended to go to the hospital as soon as possible for a clear diagnosis and active treatment.