Pain below the rib cage fan is mainly located under the rib arch. There are several reasons for this condition: 1. Diseases of the rib arch itself, such as costochondritis, intercostal neuritis, acute injury to the intercostal soft tissue and chronic strain, can cause pain in the rib arch when breathing. 2. Diseases of the organs under the rib arch can also cause pain, for example, pain under the rib arch on the right side due to cholecystitis and liver disease. Gastritis and gastric ulcer are common in the left subcostal arch, and pain in the subcostal arch will also occur accordingly. There are also lung diseases, such as pleurisy, which can be seen bilaterally in the subcostal arch and can be painful. Therefore, it is recommended to go to the hospital for a detailed examination of the pain under the costal arch, because there are still more factors involved, so as not to cause delay in treatment.