How long back pain lasts depends on its cause. For example, if your pain is caused by strain from overexertion, symptoms usually subside over days or weeks and you may be able to return gradually to your normal activities. However, you should avoid heavy lifting, prolonged sitting or sudden bending or twisting until your back gets better.
Women who have back pain caused by the added weight of pregnancy almost always will get better after delivery. People who are obese may need to lose weight before back pain eases.
People with back pain caused by pyelonephritis often begin to feel better within days after they start taking antibiotics, although they usually need to continue taking antibiotics for up to two weeks.
People with more serious forms of back pain caused by problems with the vertebrae or spinal nerves may have more persistent back pain that lasts for months and may last for years.