That sucks! Feeling bad on the top half and the bottom.
UTIs would definatley be from a catheter if you had one. I hope you're on antibiotics, because a UTI can turn into a kidney infection in less than 24hrs. Been there, done that. It actually looked like I was peeing out chunks of my kidney. Water water water! But for bladder/urethra pain get some Pyridium from your doctor. All other pain killers get filtered out before they reach your bladder. Everyone says cranberry juice helps. It does, but it's gotta be the super thick nasty unsweetened kind. No cranberry ****tail here. Because that juice tastes like crap, you can buy cranberry supplement pills. They recommend taking 1 a day to prevent UTIs . But since you have one, take as many as you want. Personal story here: I knew I was getting a UTI cuz I could feel it. So I was taking 10-12 cranberry pills a day and loads of water for 2 days until I was able to get to th doctor. We did a dip stick test, and no UTI... Well I figured I could stop taking copious amounts of cranberry cuz there was no UTI, 2 days later I went back and tested positive. Point of that story, Cranberry works.
As for gas pain, I'm sorry I have no advice. I lucked out with practically no has pain after surgery.
Hang in there!