Sleeping at night when the calf belly uncomfortable, commonly have the following aspects of the reason: 1, may be the lower limbs during the day to do a long time of physical exercise, or walking for a long time leading to the calf back muscles, fatigue and the emergence of uncomfortable situation, usually rest 1-2 days symptoms will improve. 2, may be the calf back muscles muscle strain, or muscle inflammation caused by the lower limbs often 3, there may be neurological discomfort, such as lumbar disc herniation, lumbar spinal stenosis or lumbar spondylolisthesis compression of the nerve roots of the lower limbs, which will also appear in the muscles or skin of the back of the calf, nerve sensory abnormalities and discomfort.