Stack height difference

Does anyone know the stack heights of Specialized Comp road shoes vs Diadora Cosmos shoes? I have been riding Cosmos for 5 years and now switched to Specialzed. I am having a hell of a time figuring out my position. My legs don't hurt, just have a sore right ass cheek all of a sudden. The first response would be saddle too high, But I am not too sure. I feel like (feel being the operative word) I am sitting too far back on the saddle. IF someone can provide the different stack heights of these two shoes I would greatly appreciate it.
Frinton