The pain in the calf is suddenly severe in the middle of the night: 1, it may be because of a special activity before going to bed or excessive exercise during the day, resulting in a slight strain of the calf muscles, due to the state of excitement did not feel fatigue, and the pain suddenly increased after relaxing at night when sleeping. 2, itself exists lumbar disc herniation, coupled with incorrect sleeping posture, resulting in acute phase of the disc compression nerve 3, the calf is overworked, the muscles are in a relatively tense state, coupled with sleeping at night, the warmth measures are not appropriate, there is poor local blood circulation in the calf, causing severe pain in the calf. 4, due to fasciitis of the calf or tibial periostitis, resulting in excessive fatigue during the day after the inflammation aggravated at night, causing 5, more serious because of the bony or soft tissue malignant tumor of the calf, will lead to the sudden emergence of severe pain symptoms in the calf. Therefore, if there is no relief within a short period of time, you must go to a regular hospital in time to improve the relevant examination and choose a reasonable treatment method after clarifying the cause, so as not to delay the condition.