Walking outer calf pain, may be muscle strain, trauma, lumbar disc herniation, pear-shaped muscle syndrome and other factors. 1. Muscle strain: If you have recently conducted a super-intensity, overloaded sports, easy to cause calf muscle strain, resulting in the calf lactic acid can not be metabolized in a timely manner, resulting in a large number of lactic acid accumulation, which can cause calf muscle pain, then there will be the phenomenon of walking calf pain on the outer side of the phenomenon. 2. Trauma: If the outer calf is hit by direct external force, resulting in fibula fracture, it will cause obvious pain and localized swelling of the outer calf, and walking will aggravate the pain symptoms, and it is recommended to brake immediately and carry out reset treatment in time. 3. Lumbar intervertebral disc herniation: If the protruding nucleus pulposus irritates and presses the lumbar nerve root, it will cause pain on the lateral side of the calf, accompanied by numbness of the skin, sensory dysfunction and other symptoms. Lateral calf pain can also occur when walking. 4. Piriformis syndrome: often due to the sciatic nerve in the pyriformis muscle area by the pressure caused by the early onset of the disease, to the buttock pain, when the symptoms are serious, it will compress the sciatic nerve, resulting in walking calf pain, accompanied by numbness, weakness. If the pain on the outside of the calf persists, it is recommended to go to a regular hospital for a clear diagnosis and targeted treatment.