The most common causes of sudden severe back pain are acute lumbar sprain, urinary stones and trauma. 1. Acute lumbar sprain: if the patient to carry out strenuous exercise, improper posture is easy to cause lumbar muscle sprain, and then sudden pain in the waist, may also be accompanied by skin redness, swelling and other symptoms. 2. Urinary stones: If the patient himself has urinary stones, when the position changes will easily cause the stones to stimulate the ureter and the surrounding mucosa, which in turn involves the lumbar and surrounding pain. 3. Trauma: If the patient’s waist is hit by an external impact, it is easy to appear soft tissue damage, and then appear waist pain, pain is intense but also X-ray examination, in order to prevent the fracture. Caused by a sudden back pain causes more, may also be associated with lumbar disc herniation, lumbar spondylolisthesis and lumbar spine fracture and other reasons, if the symptoms continue to have no relief, it is recommended to promptly go to the hospital to find out the cause of the disease, by the doctor targeted treatment.