Strong Shoulder Jar

Help! Weird problem, very unusual. What is it!?

Every now and then, I get this feeling that sort of runs up my spine and inside my chest feels like something is tightening up a bit. A split second later, a feeling like a jolt shocks my body...usually my shoulders, spine and upper chest feel it. It's not like an electrical shock, it's hard to explain, but it's very jarring. Sometimes it happens so sudden and comes on so strong, I actually shout out in surprise...but I wouldn't describe it as a tourette's tick...it's not a twitch and a shout...it's a crazy sensation and the sensation is so surprising, I yell. It usually happens just every now and then, though sometimes it happens more often for a matter of time and fades away. What could this be?

not sure i completly understand but ill try to explain the feeling i have.. i get a tingly sensation up my spine around my neck and near my chest. i just end up blurting out brrrr like cold.. haha its just a random thing ive always had.. it kinda feels cold but sometimes its like 90 degress out and i say brr.. it doesnt mean im cold its just what ive always said and usually say when it happens its not a twitch for me either or a dissorder. its just a sensation of ur emotions i guess i would explain mine as.. i hope this helps.. im pretty sure i know exactly what ur talking about tho. cuz i have it too sometimes its not constant just happens sometimes