There are many reasons why the left calf feels sore, including left leg sprain, cold, excessive exercise, lumbar spine disease, and so on. 1. Left leg sprain: such as walking or sports, resulting in left leg muscle, ligament strain or sprain, and cause calf soreness, pain. 2. Cold: such as blowing the air conditioner on the legs in summer, cold legs in winter; or living or working in a cold environment for a long time, it is easy to cause poor local blood circulation, resulting in spasm of the leg muscles, and symptoms such as soreness and numbness. 3. Excessive exercise: If you do not exercise occasionally strenuous exercise, or long time running, heavy physical labor, resulting in excessive accumulation of lactic acid in the body can not be metabolized in time, thus appearing lower limb muscle soreness and pain. 4. Lumbar spine disease: such as lumbar disc herniation or lumbar vertebral body slipped, are easy to compress the nerve, resulting in innervation of the lower limb area of radioactive swelling, pain, numbness. In addition to the above causes, cervical spondylosis and pyriformis syndrome can also cause the above symptoms. If the above symptoms are severe, or if the symptoms persist without improvement, the patient should go to the hospital in time to identify the cause of the disease and give targeted treatment.