Time to try saddles.
1) If your bars are lower than the saddle, make them even.
2) There are saddles made for that riding position. I use a B17 Champion Special,
and I also like the SelleAnatomica Titanico.
3) If that doesn't work, the next step is a saddle with springs like the Brooks Flyer.
4) Larger tires make for a cushier ride. I use 32c and next year I may go to 35c.