I feel for you there bro, I have had the exact same thing in the past and am still bothered with it occassionally, I stopped doing skull crushers for a while and it went away but, as soon as I started it up again it came back, I also get it from front press, I take the bar down to touch the chest before driving it back up and right at the lowest point the tendon always gives me a nasty shock. Also get numbness like pins and needles in my hand and fingers. I cured it by changing to a 1 body part a day routine.