Lumbar back pain at night can be caused by lumbar back overactivity, lumbar back musculoskeletal inflammation, lumbar intervertebral disc herniation, ankylosing spondylitis and other factors. 1. Excessive activity of the lumbar back: engaging in physical labor such as carrying heavy loads during the day, or prolonged lumbar strenuous activities can lead to obstruction of blood circulation in the lumbar back muscles, and accumulation of local lactic acid metabolism, which can cause soreness and discomfort of the lower back at night when you sleep. 2. Lumbar back myofasciitis: trauma, long-term lumbar back overactivity, long-term cold and wet environment can trigger lumbar back myofasciitis, localized aseptic inflammation, inflammatory reaction can occur at night when resting, stimulation of the lumbar back pain performance. 3. Herniated lumbar intervertebral disc: Sleeping at night due to improper lumbar posture, inappropriate bed boards, etc., can lead to increased pressure on the spinal cord and nerves in the spinal canal, which can lead to numbness, pain and other discomforts in the lower back. 4. Ankylosing spondylitis: Ankylosing spondylitis is also characterized by nocturnal pain, mainly due to slow blood circulation at night, inflammatory foci are not easy to dissipate and decompose, and inflammatory substances can lead to increased local swelling and pain symptoms after aggregation. When back pain occurs, you should consult a doctor in a timely manner, and under the guidance of a specialized doctor, you can actively carry out appropriate treatment to help alleviate back pain and other uncomfortable symptoms as soon as possible.