If a patient has back pain on both sides, it may be related to the following causes: 1. There may be lumbar muscle strain. This condition is most common among patients who sit and stand for a long time, or repeatedly bend over to pick up things. The former is often seen in white-collar workers or drivers, while the latter is often seen in heavy manual workers. The former is often seen in white-collar workers or drivers, while the latter is often seen in heavy workers. Both types of patients suffer from over-activity, which leads to strain on the lumbar muscles and subsequently produces bilateral low back pain. 2. Fasciitis may exist. This is often due to previous trauma to the lumbar region or a cold in the lumbar region, resulting in a sterile inflammation of the deep fascia of the lumbar region, which then causes pain. The pain may be widespread, may be bilateral, and may even involve the back of the shoulder. 3. It may be caused by internal diseases. If there is bilateral nephritis or gynecological inflammation, it may also cause bilateral low back pain at the same time.