If a patient has pain in the left side of the back under the scapula, it is important to first rule out trauma and external forces that may have caused the scapula fracture or soft tissue contusions around it. Secondly, after ruling out trauma, consider high-risk pain, such as acute pulmonary embolism, aortic coarctation, left-sided tension pneumothorax, or the presence of acute coronary syndrome, which can cause pain in the left subscapularis of the back. Then peripheral chest pain including cardiogenic diseases, such as coronary artery disease, unstable angina, myocarditis, and pericarditis, can present with pain in this region. Then respiratory diseases, such as patients with a large lung infection on the left side, or a pleural effusion can also present with pain under the left scapula. Finally, there are mild risk factors for chest pain, such as intercostal neuralgia on the left side, or pain in the presence of shingles.