For causes of leg pain at night and not during the day, as follows: 1, leg muscle injury, strain: this is often related to a large number of sports during the day, in the process of sports, there may be leg muscle strain or muscle microfiber rupture, while there will be a large amount of lactic acid accumulation in the legs, in the daytime state of excitement, and does not show local pain or do not feel the muscle soreness, pain 2, calcium deficiency: calcium ions can inhibit the excitability of the neuromuscular junction, when calcium deficiency increases neuromuscular excitability, it will cause cramps in the calf, resulting in spastic pain, the typical performance of calcium deficiency is that the calf cramps at night will be very obvious.