Left subcostal pain may be caused by intercostal neuralgia, costochondritis, shingles and other diseases. 1. Intercostal neuralgia: intercostal neuralgia may be caused by thoracic spine degeneration, thoracic spine injury, viral infection, physical stimulation and other factors. Patients may have pain along the ribs in the back of the chest, which is distributed in a semi-circumferential shape, and may be unilaterally involved or bilaterally involved at the same time. 2. Costal chondritis: Costal chondritis may be caused by viral infection, chronic strain of the ligaments of the thoracic and rib joints, endocrine abnormality, low immunity and other factors. Patients may have pain in the rib cartilage area, which may be aggravated by coughing and deep breathing, and manifested as pain under the left rib. 3. Herpes zoster: Herpes zoster is mainly due to varicella zoster infection. Patients experience localized pain, rash, papules, blisters and other symptoms, manifested as pain under the left rib. There are many causes of left subcostal pain, and patients are advised to go to regular hospitals to find out the cause of the disease. Once diagnosed, you need to actively cooperate with doctors to take relevant treatment measures.