If the patient has pain inside the left scapula in the back: first, we should rule out whether it is caused by trauma, if the scapula is traumatized resulting in a fracture or if the surrounding ligaments, soft tissues, or joints are damaged, the symptoms of pain inside will appear. Secondly, if trauma is ruled out, the pain inside the left scapula should be considered cardiogenic factors, such as coronary atherosclerotic heart disease, unstable angina pectoris or myocarditis, pericarditis and other conditions will have painful symptoms and sensations. Finally, for respiratory system diseases, we should consider whether suffering from pneumothorax or pulmonary embolism, there will also be pain on the inside of the left scapula, and lung infection or pleurisy on the left side will also lead to pain on the inside of the left scapula.