Standing for a long time calf swelling and pain may be due to calf muscle strain, varicose veins of the lower extremities, lumbar disc herniation and other factors. 1. Calf muscle strain: due to stand for a long time easily lead to poor blood circulation in the lower limbs, while standing for a long time the calf muscle soft tissue pulling spasm is damaged, so that the calf muscle overstrain, thus appearing calf swelling symptoms. 2. Varicose veins of the lower limbs: If you suffer from varicose veins of the lower limbs, it will easily lead to slower blood circulation in the lower limbs, and elevated venous pressure will cause the symptoms of calf distension. 3. Lumbar disc herniation: when standing for a long time, it will aggravate the pressure of the lumbar disc, when the lumbar disc herniation presses the nerve root, it may appear the lower limbs and calves symptoms of swelling and pain. Standing for a long time calf swelling pain may also be due to other reasons, it is recommended to go to the hospital in a timely manner after the relevant examination, under the guidance of the doctor for treatment.