Mimi,
I wouldn't do anything that leaves you feeling more uncomfortable. I really don't think it will help. I remember reading tons of garbage on the internet that said exercise would bring blood flow to that area and could help. I walked around the neighborhood, jumped on the treadmill and repeated that routine for weeks. It didn't help at all. As a matter a fact, I recall developing my skin tag around this time (happens with a chronic fissure) and all the exercise made it worse with the friction, it grew and became more painful.
I think your best shot with healing this are the baths, ointment,diet,stool softener and valium. It's just my opinion, Mimi but I wouldn't wait for ages to get the surgery once the fissure becomes chronic(older than 6 weeks). I'd give it all I could with the things you have been prescribed by the CRS and then talk about the next option. There's no need to suffer with this forever. We have a boardie who healed her fissure with the ointment (diltiazem) so it is possible. Just don't let it overwhelm you if everything you are doing doesn't heal it. I did and it really depressed me. I felt like I had failed. I did everything by the book and it still wouldn't heal. There's only so much we can do and hope and pray it works. The surgery works so if all else fails, just know there is a way out of this crap!
Screw the exercise if it's causing you to feel worse.