Studies have found that low back pain is the most common source of pain. It is also the leading cause of disability in Americans under 45 years old. Back pain may be the result of an injury or associated with certain diseases and conditions. Some conditions and diseases which may cause back pain are scoliosis, arthritis, spinal stenosis, pregnancy, kidney stones, endometriosis, fibromyalgia, infections, tumors, or stress. Tense muscles, spasms, ruptured disks, and other disk problems are also causes of back pain. Exercise, a diet to maintain a healthy weight, and learning to lift properly will prevent back pain.