There are more diseases that cause pain in the lower left side of the rib cage, such as soft tissue pain due to traumatic impact, intercostal nerve pain due to cold infection, etc., pneumothorax, pleurisy, heart disease, pancreatitis, splenic infarction, kidney stones, intestinal disease and other conditions. The most common cause in adolescents is stomach disorders. There are more tissues and organs included in the lower left side of the rib cage, so pain in the lower left side of the rib cage needs to be analyzed on a case-by-case basis: diseases related to the chest in the lower left side of the rib cage include pleurisy, pneumothorax, intercostal neuralgia, soft tissue injury, and myocardial ischemia. Diseases related to the abdomen below the left side of the rib cage include: acute/chronic pancreatitis, bile duct stones, splenic infarction, kidney stones, intestinal inflammation, ulcer perforation, etc. All of these diseases need to be identified by a professional by taking a medical history, nature of pain, duration, etc. or require relevant ancillary tests to determine. Therefore, the pain in the lower left side of the rib cage may cause pain in the lower left side of the rib cage due to the presence of several organ tissues around it, such as the chest, lungs, heart, bile ducts, pancreas, kidneys, intestines, etc. Each of these organ tissues may cause pain in the lower left side of the rib cage when lesions occur.