Sudden back of the head pain may be physiological factors, but also may be caused by pathological factors, such as brain diseases, tension headache, intracranial lesions, etc., should be timely consultation to identify the cause. 1. Physiological factors: if the patient is in a state of prolonged fatigue, tension and lack of sleep, sudden back of the head pain may occur. 2. Pathologic factors (1) Brain diseases: If the sudden pain is caused by a bump on the back of the head, it is due to trauma. If the sudden pain in the back of the head is accompanied by severe vomiting, it may be due to increased intracranial pressure, which can be seen in cerebral hemorrhage and cranial space-occupying lesions. (2) Tension headache: the duration is as short as half an hour and as long as several days. Bilateral occipital or whole head tightness or pressure headache, will not be accompanied by nausea or vomiting. (3) Intracranial lesions: for example, subarachnoid hemorrhage irritates the meninges, causing neck resistance and meningeal irritation sign, which causes sudden headache. If physiological causes are excluded, one should consult a doctor in time for an auxiliary examination to clarify the cause and treat the symptoms.