If a patient has a tingling sensation under the left rib cage, the following points should be considered: First, consider that the patient has high-risk chest pain, such as acute coronary syndrome, aortic coarctation, and tension pneumothorax, which have low morbidity but high mortality and must be treated actively with hospitalization once diagnosed. Second, for moderate-risk chest pain, a tingling sensation under the left rib cage is present in diseases including coronary angina pectoris, myocarditis, and severe heart failure. Third, for diseases of the respiratory system, commonly pleurisy, massive lung infection, and pleural effusion, there will also be stabbing pain under the left side of the rib cage. Fourth, for mild and dangerous chest pain, such as intercostal neuralgia and herpes zoster pain, this will also be manifested. Fifth, female patients with lobular hyperplasia, acute mastitis, occupancy, and tumor of the left breast will also have the above symptoms.