My experience is very similar to Serenity 08....I used to get the electric shock feeling in my teens and twenties periodically....it would usually go along with my "hair hurting" which sounds weird, but it was really just sensitivity on the scalp which would be irritated when I touched my hair.
It occurred either when I was sick or wore a hat for a long time. ( I have a big head and most hats are way too tight...they tend to restrict blood flow to my scalp...and probably more than that...)
Well I'm 38 now and haven't had it in a long time...but the pain fired up again a couple days ago...I have a shaved head now, so yes I notice a dent at the worst location...which I'm sure was most likely there when I was younger, but couldn't notice....
Not that I'm a doctor, but I do not believe it a serious problem, to all those worrying...I've had it before and it always resolved, and anyone on this post that has had serious tests done has had nothing found.
I believe that there are a combination of factors that most likely make this occur. I think that sinus congestion and/or susceptibility to migranes is one contributing factor ..... as most people complaining are showing one or both of those problems...and most of the time I get it I have sinus issues.
Of course it doesnt happen everytime I have sinus issues...so there must be something else....I'm fascinated by those reporting issues with the head muscles...and their possible relation to diet and/or steroid use.....
I eat like crap, so it would be no surprise to me if one of the magic combinations for my occurrences is vitamin deficiency causing some head muscle issue, combined with the sinus pressure to produce the head dent/electric shock disease....(HDESD)
If anyone finds anything conclusive please post....I'm going to address my sinus issues and start taking some vitamins....