There are two main reasons for the pain inside the ribs of the left back: first, due to strain or strain of the muscles, tendons and ligaments in the left back position, such as violently bending and lifting heavy objects, or sitting for too long, it will lead to strain or strain of the muscles, tendons, ligaments and other soft tissues in the position, which will form a sterile inflammatory lesion, and the inflammatory metabolites will stimulate the The inflammatory metabolites will stimulate the peripheral nerves and cause pain; and it is often accompanied by cold, which leads to a slowing of blood circulation and accumulation of inflammatory metabolites, which will also lead to a significant increase in pain. Secondly, due to the problems of the left kidney, the common ones are kidney stone, kidney cyst, hydronephrosis and kidney tumor, all of which will squeeze the surrounding tissues and stimulate the peripheral nerves, which will also lead to obvious pain.