I would first, make sure that you do not have a bacterial infection. I had one in the beginning of the season; no amount of natural cures will cure it! The symptoms were pretty much the same as a yeast infection, but the pain never abated. I would *think* it was gone, but it really wasn't. I wasted 6 weeks like this, when all it took was a quick check by my gyn. and a prescription. She said my numbers were "off the charts." I had never had one before, so it never crossed my mind.
I started washing my shorts in HOT water after this. I know, all the tags say don't do this, but I haven't had a problem since I started this. And, I am very vigilant about changing out of my shorts after riding; no sitting around and eating and socializing. My extra pair of loose shorts go in the car with me for events/rides.