Hi,
Low back pain is usually caused when a ligament or muscle holding a vertebra in its proper position is strained. Vertebrae are bones that make up the spinal column through which the spinal cord passes. When these muscles or ligaments become weak, the spine loses its stability, resulting in pain. Because nerves reach all parts of the body from the spinal cord, back problems can lead to pain or weakness in almost any part of the body.
Some ways to relive the pain are, Using a heating pad or hot water bottle, Resting in bed on a firm mattress, ,Take OTC pain lillers, Wearing a belt or corset to support your back.
I hope this helped you.
Best regards.