I'm not saying the OP is doing this, but there are some riders who sort of plop themselves down in the saddle, and slouch, as though they were sitting in their office chair or easy chair or something. You've got to think of sitting on the saddle as "perching" on the saddle (on your sitbones) ... and in order to do that, you've got to have a saddle that is wide enough, as well as some abdominal and back strength to hold the body in position. This may seem uncomfortable and awkward at first, but in the long run, it's a lot more comfortable.

And I've ridden saddles that were too narrow ... very, very painful.