Sometimes it isn't the saddle but the shorts. Shorts that are too tight can add to the effect of saddle pressure in critical places. Also padding which has sometimes become excessive adds to the problem because it transfers pressure form the "sit bones" where you can handle it, to more central areas where it cuts off circulation.

So padded saddles and shorts are a mixed blessing, often trading less saddle soreness for numbness other places.

If this is a new problem for you, and you're been riding without it for a while, the first question you need to ask, is "what changed". The answer will help point you in the right direction, unless of course if you're just riding longer.

One thing that does help is to stand or at least lift slightly off the saddle for a short interval from time to time. I rarely or never have this issue riding the rolling terrain where I live, but sometimes see it happen on long flat rides. The only difference is that climbing rakes weight off the saddle in ways that pedaling along on the flats doesn't.