If it does not extend beyond your elbow, meaning no closer to your shoulder it could be a type of tennis elbow and after having steroid shots in my elbow the surgeon told me of a stretching exercise that has saved me from having to ever go back.....you stretch your arm straight out and then make a fist, pull the fist down under itself (toward the inner arm itself) and hold that position for 30 seconds, doing it ten repititions a few times a day.....it always saves me, hope I was clear....you should feel the tension pull on the top of your arm (between the hand and elbow topside of arm). Good luck!!
Sounds like nerve pain which truly is painful. Depending which nerves are involved it could be from a neck or carpal tunnel injury. Please get it checked out because it only gets worse
Goof luck
Ginger