Hard back pain may be caused by lumbar muscle strain, lumbar disc herniation, lumbar spinal stenosis and other conditions. 1. Lumbar muscle strain: It is usually caused by chronic, cumulative or mechanical injury to the lumbar muscles, and is also related to factors such as long-term weight-bearing exercise and improper handling of heavy objects. The symptoms of lumbar pain or distension often appear, and can also radiate to the buttocks, and some patients can also appear lumbar hard pain phenomenon. 2. Lumbar intervertebral disc herniation: it is usually caused by long-term work, degeneration of intervertebral discs, abnormal development of lumbar vertebrae and acute trauma. Lumbar pain and sciatica symptoms often occur, and lumbar spine mobility is reduced, decreased muscle strength, which can also be manifested as lumbar pain. Some patients may also experience radiating pain and numbness in the lower limbs. 3. Lumbar spinal stenosis: usually caused by congenital hypoplasia of the spinal canal, but also related to ligament hypertrophy, trauma, inflammation and other factors. The symptoms of lumbar back pain will often appear, which will be aggravated when standing or walking in the lower limbs, and lumbar stiffness and pain can also occur. Some patients may also show sciatica, intermittent claudication and so on. When the symptoms of lumbar stiffness and pain appear, you should consult a doctor in time to clarify the cause of the disease, and target treatment under the guidance of the doctor.