When you say that your crotch hurts, just exactly what do you mean. Does it sting, ache, is it a dull pressure type of "hurt"? Is it a pinching sensation? Is it at the skin surface, or within the tissue type of pain? What are you trying to say?
By your description, the crotch is an area as big as the saddle. So, where exactly does it hurt? With all the bundling up, it's very possible that you have a couple of wrinkles or seams that are folded over and creating a pinch or a pressure ridge.
More specific info please.