It sounds like a spasm or contraction of some kind...You said it's happened twice but what were you doing each time..Did yu move youre head quick Id your throat tighten as well There really isn't alot of information to go on..But since it has happpend twice I would still bring it up with my doctor..Write down everything-what oyu were doing at time it happend, did it burn, sting, shooting or radiate out to another area. Exactly where in the nexk did this happen and exactly where in the back..Did yo feel anything in any other area?