Catheters would not hurt if put and removed smoothly. For too sensible peoples, the use of "lidocain gel" for insertion will anaesthetize the urethra for the short time of the insertion.
While in place, a catheter will not hurt. If it does, there is something wrong and it will be removed or changed imediatly.
I'm using caths since a pretty long time and never had any health problem with it.
I've read some peoples having trouble with painful caths procedure. Yes, it can be... But in great major time, if done properly, with good sterile procedures, there is no pain at all.
While writing this post, I'm one more time cathed (since 5 days now), and can't notice I've something inside my penis! To prevent UTI, I drink a lot (more than 3 litters per day). If I don't, I use at bedtime a NG tube to take 1 or 2 litters.
I like so much to be under such control that I'll don't want to have any problem!
BUT: remember... It's never a really safe game! Be aware of all possible side effects before doing it.