Long story short, I've been struggling with chronic pelvic pain and interstitial cystitis/painful blainful syndrom for a decade. I also have two herniated discs in my back. Both of things have mostly kept me out of the saddle for a year and a half now. I know I'll never compete in barrels or competitive trail rides anymore, but I'm hoping somehow I can still pleasure ride on my own ground. Does anyone have any tips on where to buy or how to make my own saddle seat cushion? A standard riding cushion won't work... I need it to be hollow in the middle. I have this one I take with me everywhere to sit http://theraseat.com/shop-products/#!/Oval-Thera-Seat/p/50152608/category=15239228, but it's way too big for a saddle. I'm not creative or crafty at all, but if any of you DIYers have tips, I have people who have volunteered to make it happen!

What brand of saddle are you useing now? Is it a wide tree or a reg.?

I ride in two different Bob Marshall treeless saddles... the trail/endurance model and the barrel model

i ride in a treeless sometimes too, and I have found on my wide back gelding that my pelvic area will get sore if I ride him to long in the treeless like a roping saddle, the twist area gets to wide for me sitting on his wide back. But if I ride him in a treed saddle that dont happen to me, I think since its a treeless it sits flatter on the backs so that makes them a bit wider, but if I have my treeless on my narrow gelding the pelvic pain is not there. 

Check with the endurance sites...they have all kinds of things to make the tushy more comfortable.