saddle or rear end pain in only a mile or two is far too soon. I wouldn't be shopping saddles, but instead try to identify what's wrong, where it hurts and why. Saddles do make a difference, but mostly on longer rides that are hours, not minutes long.

It could be that your saddles aren't supporting you in the right place, the angle may be wrong, they may be too wide or too narrow, or you may have some tendonitis back there that the saddle in aggravating. Take the time to try to sort things down to a short list of causes, then try a few saddles, focusing on shape, angle and fit, before worrying so much about the material.