Soreness on both sides of the waist when bending over is considered to be caused by excessive exercise, myofasciitis, lumbar intervertebral disc herniation, ankylosing spondylitis and other reasons. 1. Excessive exercise: excessive lumbar exercise or excessive bending strain, can cause lumbar muscle lactic acid accumulation, causing lumbar soreness, generally physiological, can be relieved after rest. 2. Myofasciitis: lumbar myofasciitis is caused by strain, trauma, cold stimulation, etc. These factors can cause aseptic inflammation of the lumbar muscles and fascia, which can lead to bending back and waist soreness on both sides. 3. Lumbar disc herniation: lumbar disc herniation is caused by degeneration of the lumbar disc, with age, there will be a rupture of the annulus fibrosus, when the nucleus pulposus protrudes through the rupture of the annulus fibrosus, it will be stimulated for the peripheral nerves and other tissues, which will cause pain and soreness in both sides of the waist. 4. Ankylosing spondylitis: a chronic inflammatory disease, the main lesion site for the sacroiliac joints, spine and peripheral joints, can also cause bending back pain. There are other causes of back pain, such as trauma, etc., if the rest does not relieve, you should go to the hospital for further examination in a timely manner, to clarify the cause of the disease and follow the doctor’s instructions for targeted treatment, so as not to delay the condition.