Left lower back pain at night, no pain during the day, usually considered to be a bad sleeping position, cold, lumbar muscle strain and other reasons, the patient can be adjusted through the sleeping position, physical therapy and medication and other ways to alleviate the treatment. 1. Poor sleeping posture: This may be caused by physiological factors such as poor sleeping posture. Generally no special treatment is needed, and patients can improve by adjusting the sleeping position and paying attention to keep warm. 2. Cold: Due to the low temperature at night, if you do not take good warming measures when sleeping, it is likely to cause the left lower back to be cold, and the phenomenon of pain, and after the daytime activities, the lumbar blood circulation to speed up the symptoms will disappear. Patients can have physical therapy and hot compresses on the lumbar region to help improve blood circulation in the lumbar region, so as to achieve the purpose of relieving the pain in the lumbar region. 2. Lumbar muscle strain: If the patient’s pain symptoms are obvious, it may be caused by lumbar muscle strain. Patients can also be relieved by hot compresses, if the effect is not obvious, you can also follow the doctor’s instructions to take celecoxib, losoprofen sodium and other drugs for treatment. To sum up, there are other causes of this phenomenon, if the condition has not improved, it is recommended that the patient consult a doctor in a timely manner for examination, to clarify the cause of the disease, under the guidance of a professional doctor, targeted treatment.