Most of the time back pain in children is caused by an overuse injury or mechanical problems. Occasionally, there may be a ruptured disc or problems in the muscles or bones that the child has from birth. But the most common reason is a direct injury, since children are normally falling all over the place and rarely take the precautions that adults do. This is because natural reflex is not fully developed in younger kids. Even a minor fall can lead to a pulled muscle or torn ligament and worsen into severe back pain.

Children may also suffer from spondylolysis (fractures in the spine) and spondylolisthesis (slipped disc). Bad posture while studying, watching TV or playing is a major contributing factor to early disc problems, though the latter is a rare occurrence,.

Infections and inflammations are another common reason behind childhood back pain. In such cases, the tell-tale signs are fever, weight loss, weakness, or nausea. Tuberculosis of the spine (Pott's Disease), Pyelonephritis (kidney infection), and infections in the disc are some of the usual inflammations occurring in children.

Other and much rarer reasons of underage back pain include tumors, malnutrition, arthritis etc.