About 8 in 10 people have one or more bouts of low back pain. In most cases, it is not due to a serious disease or serious back problem, and the exact cause of the pain is not clear. This is called non-specific lower back pain. The usual advice is to keep active, and do normal activities as much as possible. Painkillers can help until the pain eases. In most cases, the pain clears within a week or so but may recur from time to time. Chronic (persistent) pain develops in some cases, and further treatment may then be needed.