Possibly you could have a nerve just going haywire! I would personally recommend a chiropractor and/or heat and Ice treatments. If it gets worse then consult a chiropractor it will help ALOT! Wish you the best
It sounds like tentinitis elbow if so its not serious.
I have a similar issue & it was diagnosed as the nerve in the elbow, the one we call the crazy bone but its actually a nerve that runs through the elbow. there are times it seems hard to stretch my arm completely outward if i keep it in a bent position too long. from what i understand it is better to live with the pain than the results that could take place from having surgery on it so i opted to live with it for as long as i can. hope this helps.