The bump that I had came on with out any reason either. I ride almost everyday, whether it be on my road bike, inside on my lifecycle or spinning at the club. All three have different type saddles, and I wear different shorts. So I still don't know what caused it. Since I had the last one, I haven't changed anything and it hasn't been back. I think sometimes these pesky little things just pop up and go away on their own. I suspect it was a spot that was slightly irritated (probably from cycling) and just took on a life of its own. Hopefully your doc should be able to identify and maybe give you some ideas to speed up healing or at least provide some comfort while it is healing. Let us know what you find out. Good luck!