Sudden pain in the calf, may be caused by certain physiological factors, may also be the symptomatic manifestation of certain diseases, such as lumbar intervertebral disc herniation, hypocalcemia, etc., and should be promptly consulted to identify the cause of the disease. 1. Physiological factors: Due to overwork or strenuous exercise, lactic acid can accumulate in the calf muscles, causing calf soreness and pain, which can be gradually recovered after rest or local massage. 2. Pathological factors (1) Lumbar intervertebral disc herniation: Lumbar intervertebral disc herniation can lead to stimulation or compression of the adjacent spinal nerve roots, thus causing lower limb numbness, pain and other symptoms. There may be a sudden pain in the lower leg in the innervated area which is relieved later. (2) Hypocalcemia: a disease in which the blood calcium is lower than normal due to the decrease of calcium ions in blood or the increase of calcium ions excreted in urine, which is mainly manifested by symptoms such as muscle twitching, tetany, and in severe cases, it can also lead to tracheospasm and pathological fracture. There are other reasons for the symptoms of sudden pain in the calf, if it continues to be unrelieved, you should consult a doctor in time, improve the relevant examination, clarify the cause of the disease, and actively cooperate with the doctor’s treatment, so as not to delay the condition.