Muscle soreness in the thighs as well as the calves has the following causes: First, it may be caused by strain. People who often stand or walk, the muscles of the lower extremities are prone to strain, especially after standing for a long time during the day, and at night there will be soreness. Second, it may be caused by strenuous exercise. After strenuous exercise of the lower limbs, lactic acid accumulation in the muscles will occur, thus stimulating the muscles and causing muscle pain. Third, it may be a nerve symptom, such as lumbar disc herniation, lumbar spinal stenosis or pear-shaped muscle syndrome, compression of the sciatic nerve will also cause nerve pulling pain, numbness and weakness in the lower limbs, so it will also cause pulling pain and soreness in the muscles of the legs.