Chest pain on the left side when sneezing may be due to diseases such as costochondritis, intercostal neuritis and bronchitis. 1. Costochondritis: Costochondritis is usually associated with strain on the ligaments of the rib joints, viral infections and autoimmune conditions, and may also be caused by trauma or surgery. When this disease occurs, it will cause chest pain, localized redness and swelling and other symptoms, sneezing will cause chest force, causing the left side of the chest pain to worsen. 2. Intercostal neuritis: intercostal neuritis can also cause patients to sneeze when the symptoms of left chest pain, this disease in the less severe symptoms, will cause local burning sensation, hidden pain and other symptoms, sneezing will cause chest force, causing left chest pain. 3. Bronchitis: bronchitis will cause patients to cough, cough sputum and other symptoms, some patients will also be accompanied by fever and symptoms of runny nose, inflammation is serious, the patient will cough, sneeze, one side of the chest pain. The left side of chest pain when sneezing may also be other reasons, such as trauma, digestive system diseases, heart disease, etc., should be timely to the hospital for examination, clear diagnosis, active treatment.