Ever since I can remember I've always had trouble with people touching my back or my bum, when touched by even myself lightly or with some pressure I get horrible electric shock pains all the way down my back, mainly focused either side of the bottom of my spine just above my bum and in the very centre of my spine. I've had this for years and it's never got better or worse but am intruded to know what is causing it or if it's a common thing