Most back pain is caused by injury to the lower back or an ongoing condition. Overuse of the back muscles, sports injuries, extreme lifting, or sudden jolts -- such as a car accident -- are examples of injury. Arthritis or a bulging disc are ongoing conditions that may cause back pain.
Acute – or short-term – low back pain begins suddenly and may last several days or weeks. Chronic low back pain, which can be mild or severe, lasts longer than three months.