Back pain may occur in the upper, middle, or lower back. However, it is most often experienced in the lower back. It may originate from the bones and ligaments forming the spine, the muscles and tendons supporting the back, the nerves that exit the spinal column, or even the internal organs. Back pain can range from mild, annoying discomfort to excruciating agony. Depending on how long it lasts, it can be described as acute or chronic.