The causes of calf soreness at night are overwork, fasciitis, varicose veins of the lower limbs, etc. 1. Excessive exertion: if the patient during the day strenuous exercise, high-intensity work, etc., resulting in excessive physical exertion, frequent contraction of the leg muscles, resulting in a large number of lactic acid accumulation in the body, which will trigger the patient’s lower limbs to appear sore and swollen symptoms. 2. Fasciitis: due to long-term exertion, standing, exercise, etc., resulting in constant pulling movement of the leg muscles, the formation of chronic aseptic inflammation, when the constant stimulation of inflammation, exudate increase, and these exudates can not be effectively absorbed at night to discharge, which will trigger the patient to appear soreness and swelling of the legs. 3. Varicose veins of the lower limbs: If the patient suffers from varicose veins of the lower limbs, due to the dysfunction of the venous valves, the blood flow of the lower limbs becomes worse, which triggers the lower limbs to have the symptoms of soreness, swelling and pain. There are many reasons for patients to have soreness and swelling of calves at night, it is recommended that patients go to the hospital in time to improve the relevant examinations, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.