I recently switched saddles because of this very same issue. My old saddle (a Terry Butterfly) suddenly became a torture device.

Now I'm riding a Terry Falcon X...got it brand new on eBay for around $35...and it's great. Much firmer and less padding, a little narrower, and a longer/wider cutout. It took a few rides to get used to the harder less cushy padding, but now it's feeling great.