I just have one piece of advice. I completely disagree with lungeing a horse to get rid of their energy. Instead, find a way to use it. On the flip side, I agree with lungeing a horse before riding for other reasons.
I am training my green broke mare, and to get her head in the game, as she is very emotional and more high strung, I will lunge her at a flat walk only. She usually starts out a little fast, but in a few minutes she slows down and relaxes. I use parelli games on her so I will ask her to back up, come in, back up, change directions. All at a slow speed.
When I was a teenager and taking lessons on a TB, he was getting very ring sour. My instructor had every student who rode him, lunge him half an hour before the lesson to get the bugs out, with the same idea, if he is going to buck, get it out on the lunge. Well that horse got in excellent shape, and it did nothing to stop his bad behaviour.
There must be an underlying cause, a pain issue, saddle fit, etc.
I agree with whoever suggested a round pen, that is a great tool, and that poster had great advice.
Good luck and don't give up!