A common cause of back pain is injury to a muscle or ligament. These strains and sprains can occur for many reasons, including improper lifting, poor posture and lack of regular exercise. Being overweight may increase the risk of back strains and sprains.
Back pain may also be caused by more-serious injuries, such as a spinal fracture or ruptured disk. It can also result from arthritis and other age-related changes in the spine. Certain infections can cause back pain.