The pain below the left side of the rib cage may be caused by the following etiologies: 1. It may be caused by rib fractures. Elderly people or patients with severe osteoporosis are very susceptible to rib fractures, such as a simple sneezing motion, which may produce rib fractures and subsequently cause long-term pain.2. It may be caused by costochondritis. Costal chondritis often manifests itself as pain around the ribs at the onset, and the pain intensifies when touched, and manifests itself as a localized swelling.3. It may be caused by intercostal soft tissue lesions, such as intercostal muscular spasm or intercostal neuritis and other diseases. The former is often due to excessive and intense activities that lead to local muscle injury, the latter is often due to infectious diseases, such as chickenpox, shingles and other diseases.4, may be due to internal organs related diseases. For the left side of the ribcage below this part, the cause of pain is very many causes, such as pleurisy, heart-related diseases or gastric disease, spleen-related diseases and so on, may lead to pain.