I have had crohns for ten years and had 1 surgery. I also have the same problem as you. I find that if I take regular light pain relief it sometimes is not as bad. I have a liquid diet 3 days a weekand light food the other days. The problem i think is scar tissue in the rectum particularly if you have skin tags inside. The lower bowel has a build up of scar tissue and when a BM is needed if you hold it back it will put stress on the area and create pain. For me it is best to just go with it and let it fly or spray as I say . It is necessary to relax as much as possible when your body tells you "I need to go now" Let me know how you go
I also feel the pain is worst if I don't have a bowel movement, and as bad as the pain is to have the bowel movement after it is done i do feel a lil relieved i get real sore and tired after but better then trying to hold it in. I usually close my eyes and take deep breathes during holding a cold wash cloth over my face. I have realized getting upset during an episode makes it much worse. I have fainted a few times also, it is really no fun at all.