A throbbing pain on the left side of the head may be caused by physiological factors, or it may be caused by migraine, postherpetic neuralgia and other factors. 1. Physiological factors: for the recent lack of sleep, mental overstress, life stress, easy to cause the left side of the head of the nerve a burst of throbbing pain phenomenon. This is a physiological factor and can often be relieved after sufficient rest. 2. Migraine: lack of sleep, psychological stress, excessive alcohol consumption and other factors may trigger migraine, it will lead to the left side of the head of the nerve throbbing pain, accompanied by photophobia, panic, sweating and other symptoms. 3. Post-herpetic neuralgia: If herpes zoster infection occurs in the skin on the left side of the head, neuralgia may appear, or cut-like, electric shock-like, tear-like pain. The symptoms of a throbbing nerve pain on the left side of the head, should seek early medical attention to clarify the cause, by professional doctors to give a reasonable treatment plan.