It's called Occipital neuralgia "... a distinct type of headache characterized by piercing, throbbing, or electric-shock-like chronic pain in the upper neck, back of the head, and behind the ears, usually on one side of the head."
http://www.ninds.nih.gov/disorders/occipitalneuralgia/occipitalneuralgia.htm
I'm in my late 40's and have had this issue since I was little. I can relate with everyone that has experienced the same extreme strange pain and symptoms and the awkwardness of trying to describe it to Doctor's, Family, and Friends.
The symptoms are primarily the same for me as I feel the extreme reflex "jerk" reaction like I turned my head the wrong way and an immediate rush of heat to the region on my head. The initial episode lasts a few seconds then it feels like a flood of warmth on my skull for 10-15 more seconds which I’ve interpreted as blood or fluid flowing outward then the residual aches and delirium of what happened for 10-15 minutes. I usually raise my hands to the area to feel the warmth if it exists externally as internally. Usually does. The location changes for me from back and sides to top of my head; never on the front side. Sometimes I get a headache from it that is longer lasting and I feel extremely sore for a while in my neck.
I never forget where I was and what I was doing when I have a bad episode. When it happens I usually cringe and verbalize. Others around me are aware that something happened but it quickly becomes evident I’ll survive and they can go about their business as I do a quick self check as well and move on. I've had to sit down and recompose many times as the pain, headache and dizziness have to subside. There is no trend in time that relief from this will come. It happens 10-50 times a year in no particular order during my life. Doctor’s have never been able to diagnose and I was flat out ignored when I was younger. I feel I’ve accepted this as a part of life and was unaware that anyone experienced this besides me. I’ve looked for this type of posting as long as I can remember and am relieved and horrified to know others feel similar symptoms.
I have shared my symptoms with friends and family and joke with those around me after that see me suffer from such events; I tell them my brain just got bigger which in turn obviously makes me smarter. My wife calls them “ticks” but I can see the worry in her eyes as we suspect something much more sinister is occurring.
I can’t wait to share with her as I feel some solace and sanity in what I have read in these posts.