Has any one ever got a shock from their electic guitar?

Has any one ever got a shock from their electic guitar as I just got a large shock off mine. Its a Yamaha RGX 312 and a Yamaha G100-112 amp
# 1

No, you should never get a shock from a guitar. If you do then it means there is something electrically wrong with your amp and you should stop using it immediately. Since your amp is plugged into the wall outlet, there is the potential for up to 120VAC (or 240VAC depending on your country) to get shocked from.
Take it in to a shop or replace it.
Take it in to a shop or replace it.
# 2

It's probably a grounding issue. Your amp has a three prong plug. If the third prong is missing or your outlet isn't grounded, this can happen.
# 3
Not from a guitar, but I sure did get bit from my microphone! Turned out to be a grounding situation, but it sure did make me shy about singing for a while LOL!
# 4