Head Tossing, Ducking, and Throwing

Pain would be my first issue to look at as well. How long off the track is this horse? Racehorses are taught to pull against pressure. They take the bit and pull, thats just what they do. Can you do the porcupine game with him with pressure on his nose to back him? He should give easily to that and not fight you. I would do alot of porcupine with him, I think he is confused with pressure and needs to learn to give more. Can you bend him from the ground?
I had this issue with my 4 year old and I ended up doing some non Parelli with him, ground driving him with the bit, making him collect and bend at the poll. I love Parelli and do all of it with my horses, but I have found that sometimes I have to resort to "traditional" training methods to work on specific problems. Some horses will "get it" when you do that, then I go back to Parelli.

I would look into your saddle and pad. Sounds like it is pinching him some where. I have the saddle fitting DVD from Parelli if you would like to have it.

my email address is debra1625@msn.com