You have one or more damaged discs and/or areas of arthritis in your back. These produce pain and may produce abnormal motion or a misaligned spine. The discs act as shock absorbers between each vertebra and are located near nerves that originate in the spine and travel down the legs. If the disc is damaged, a portion of it may bulge, become herniated, or even burst free into the spinal canal, putting pressure on the nerve. This can lead to pain, weakness or numbness in the legs.