Went on the trainer tonight for a half hour because I was going crazy. It only hurt, I'm not even sure if hurt is the right word actually, when I was out of the saddle and bouncing on the pedals. Sit and spin felt fine, no pain at all! So, if it doesn't hurt, theoretically I'm not doing damage right? I've been reading a lot on this stuff and I don't really get how biking, an activity normally recomended for post injury rehab, could cause a problem in the first place. WTF???