Pat, I am so sorry. I think Galaxy is still asking for help.
Ask the vet if he would recommend an ultrasound of the bladder, and if he would put her on pain medication. Something that's safe for cats and can be used long-term is Gabapentin (neurontin).
Let the vet do another urinalysis. How was the urine obtained last time? Did you bring a sample or did the vet get it by needle (cystocentesis)?
I try to think of other possibilities, but there is a good chance that Galaxy's problem is truly a behavioral one. Can you think of anything that happened or changed before this all started? Cats can be bothered by the tiniest thing.

I keep my fingers crossed that there will a resolution soon.
Hugs to you and the kitties.