Scoliosis is the curvature of the spine. Scoliosis may result from juvenile scoliosis in kids (unknown cause), spine, arthritis, neurologic disease, surgery, injury, etc. Neurologic disease such as a spine tumor may cause back muscle weakness resulting in scoliosis. Scoliosis is not caused from being out of shape or not working out at the gym (that is being weak). I hope this information answers your question.
For more information please click on Does scoliosis cause pain? Good luck!