Possible causes of pain under the calf tummy include sports injury, fasciitis, lumbar disc herniation, Achilles tendonitis, varicose veins of the lower limbs and so on. 1. Sports injury: after strenuous exercise or long time physical labor, lactic acid buildup or muscle strain, calf pain, soreness and other symptoms can occur. 2. Fasciitis: because of trauma, exertion, cold and so on, it causes aseptic inflammation of calf fascia, which results in pain in the calf. 3. Lumbar disc herniation: Lumbar disc herniation will compress the nerve root at the back, thus causing radiating pain in the lower limbs, which can be radiated to the back of the calf, mostly accompanied by pain and discomfort in the lower back. 4. Achilles tendonitis: because of trauma, physical labor, etc., resulting in Achilles tendon injury, aseptic inflammatory reaction, resulting in pain in the back of the calf. 5. Varicose veins of the lower limbs: because of prolonged standing, physical labor, habitual constipation, etc., causing varicose veins of the lower limbs, which manifests itself as heaviness, soreness and fatigue in the calves, and localized blood vessels can be seen to bulge. Causes of pain under the calf stomach are more reasons, may also be related to gout, lower limb thrombosis and other diseases, if the symptoms continue to be unrelieved, it is recommended to consult a doctor in a timely manner, to clarify the cause of the disease, targeted treatment.