The causes of leg muscle pain are as follows: 1, too much excessive physical activity or physical labor: these activities are very easy to cause leg muscle strain, or leg muscle sprain, in muscle injury will appear muscle fiber rupture, but also lactic acid in the muscle internal accumulation, so there will be muscle soreness, pain. 2, lumbar spine disease: such as lumbar intervertebral disc herniation, protruding disc tissue When the spinal nerve root is compressed, there will be radiating lower limb pain, and the pain can radiate to the thigh and calf. Lumbar spinal stenosis, due to the reduction of the capacity of the spinal canal, ligamentum flavum hyperplasia, and osteophytes in the attachments of the vertebrae, causes the nerve root and spinal cord to be compressed, which in turn causes the pain and weakness of the legs and a feeling of numbness.