Sounds like this diagnosis is close, General Buster(10) just had a UTI, but it was something cleared up with 2 weeks of pills 2X a day, now his Master, had a kidney stone this summer, and for that, after a night of pacing(all I could do, as had to pee every 2 minutes, and couldn’t make the car ride to a emergency room), hot tub + lots of water + mowing the lawn finally got it passed
recommend a cat drinking fountain, a second opinion from another Vet(if your not confident in this one) and
Health & Nutrition section;
http://www.catforum.com/viewforum.php?f=3
My cat had this problem years ago due to the crap cat food I was feeding him. Once we got the crystals dealt with I started feeding the C/D catfood (canned and dry). My cat lived until he was 19 years old. He died in my arms the day before Thanksgiving this year. I cried like a baby.
Never be another one like him.