Acute low back pain of unknown cause is called a Lumbar sprain.
Unlike herniated discs and spinal canal stenosis, severe pain can be cured in a few days, but it usually takes about a week or two to be completely cured.
I feel that people with chronic lower back muscle tension are more likely to have a Lumbar sprain.
Main symptoms
Repeating the same posture and movement puts a strain on the lower back muscles and causes pain in the same area.