Any suggestions?

Alright so, Ice and I have gotten over his issue with the arena, but he's a little stiff on his left turns. I know he flexes perfectly, because he turns around to look at me all the time. But, nonetheless, he stiffens up when I ask for a left turn, and instead sort of does a continuous half pass to the right....from the saddle, I can see his head is turning, but his butt is not following suit. It feels like I almost need a spur to tell him to move his hips. Also, it feels kind of like he's leaning to the right? Could it just be my balance, or could it be something else?

If it helps, he does have some sort of knot near his croup...like in the base of his spine on his left side if I remember correctly. It doesnt hurt him when I press down on it as far as I can tell, he doesn't pin his ears and lunge at me like he usually has no problem doing when I do something he doesn't like. Its not a hump, it really does just feel like a knot.....

That may be part of your problem. If I were you, I would have a vet check it out.

If it's just a big muscle knot, you can try massaging it out. Gently palpitate it with your palm to warm up the area. Then apply direct pressure to the knot for about 10 seconds to try to get it to release. Alternate between the two until it's gone. If it is just a tight muscle, your horse will react by licking his lips or yawning if you hit the sweet spot. Stand at his shoulder or at least well in front of his rear legs in case it hurts him when you first start massaging it. (don't want to get kicked) My horse had a tight knot in his shoulder last week the size of a golf ball. After 10 minutes, we worked it out and it hasn't returned.

So I went out riding earlier today, and he turned much better, I think it was just a matter of him flexing out. However, if I try for too much of a hard turn (like going around a barrel) then he reverts to the side passing.

Its not a muscle knot.....its about the size of a knuckle, and hard as a rock. It feels like maybe a vertebrae is out of position, and it completely disappears when his head is down. I actually pushed in it not only from the ground but also from the saddle and he gave me no reaction at all, so I can only assume that it doesn't hurt him....whatever it is.

When he had a similar spot in his neck, about three our four inches from his poll, my chiro and I could press on it, and his head would immediately drop and he would start yawning. That spot in his neck is gone now, so maybe it working its way out of his body? Whatever it is I'd still like to know, since my chiropractor can't seem to figure it out either.