I feel for you. I am in the same position, sort of. I have my cystoscopy last Thursday, one week ago, and I have a lot of pain also, and am also on the same pyridine and cipro you are. I also take morphine and lortabs for my spinal issues. (I have 2 burst leaking lower discs and a cyst growing on my spinal cord in my middle back). So I'm already take a LOT of pain meds.
I can hardly pee at all. I can't get the stream started. Sometimes take 20 - 40 minutes and I too cry out of frustration and pain. It feels like where my urethra and bladder meet on the inside--that is where the pain is. It hurts initially to start to pee there, and then when I push the last bit of pee out, it REALLY hurts. I am seeing my urologist tuesday. I talked to him on the phone yesterday to complain and he said to just continue to take the meds and maybe try sitting in a hot bath to relieve the sweling. Well, I don't think there IS any swelling. I think something seriously is wrong, even though he didn't find anything wrong inside my bladder, or otherwise. I dont' know what to do, but I'm like you, scared to drink a lot now, becuase what goes in has to come out.
I feel for us both! :::HUGS!::: ~Molly