I have those pedals on my commuting bike with thousands of miles on them (probably 5000). I've never had any problem. You can overtighten pedals, so maybe that's what happened. Maybe not; it's hard to tell from your description. But definitely take them to a local bike shop and see if they can fix them for you. If they can't and you decide to replace the pedals, do consider buying them from a local bike shop so you can go back if there are any problems, as well as support local businesses.

Best of luck to you. Crunchy pedals do not sound like fun.