Saddle Fit

I have this posted in my thread in the Dressage section but I thought I'd post this here since it's more relevant.

I am a little concerned because it seemed like Zeus might be sore. It was pretty slight, but turning to the left, or going left really at all he'd stiffen up, his head would go up, and he'd just feel... a bit funky. Now I lunged him before I rode, and didn't see anything. It could be that his left side is his weaker side, it could be his left front bothering him, or it could be (this is something i've been thinking the last few rides) his saddle. Here's my concern with the saddle. Sitting on his back with nothing underneath it fits great, it clears his back, it sits perfectly. What I've discovered is that with any kind of saddle pad, from a thin normal one, to a fluffier half pad I have, it doesn't fit the same. With or without the gel pad that I use. I'll tack up, check to see that there's space at least two stacked finger's height between the pommel and his back, and before I start riding there is. After I'm on and riding when I check the space, there's none. No space at all. His saddle isn't sliding and it's not too far forward.

I'm pretty confused. I can get pictures if you guys want, but his saddle does fit without any pads. When there's any kind of pad added and we start riding, it doesn't. Or, rather, seems not to. I'm no professional saddle fitter. I'm a worry wart. I'm know to be one. There may be nothing wrong, but I need to be sure. Help ease my mind?

Pictures would probably help a lot. =)

I'm sorry you're having issues! Last week was one of those weeks for me and Lacey, she was being a jerk about everything! *hugs*