Do you get a strong persistent urge to urinate?
Are you passing frequent, small amounts of urine?
Did you follow up with a urinalysis?
This doesn't sound as though it's related to any type of infection. There may be inflammation from the catheter itself. That is good that you are drinking lots of water. I would also take some ibuprofen, as if there is some inflammation going on, this will help reduce that.
You can try the Uristat to see if it will help with the burning, however do NOT take it for more than 48 hours. So if there is really no help in 24 hours, then chances are the Uristat won't work.
So try the ibuprofen, continue your water and even go ahead and drink some cranberry juice as well. If there is no change in the next 36 hours, then you will need to follow back up with your doctor, as there may have been an injury when the cath was removed etc.
If you develop a fever, if the pain gets worse or you do see any blood, then do be seen right away.
As I said it didn't sound like an infection, so I didn't think the antibiotics or the uristat would help you any. I don't know if you are still taking the ibuprofen. But at this point, I would suggest following up with a Dr. I don't know what type of surgery you had. But at this point, you may need a urologist. There may have been some trama during the insertion or removal of the cath. You may even need to have a Cystoscopy done, which will allow them to check the bladder and the urethra to see what is going on. But this far out and with what treatments you have done, you should be fine by now. So you can either check in with what you call the neighborhood doctor, just so a urinalysis can be done to rule out any possible infection. And go from there.
Do the ibuprofen, as that helps with inflammation. And if there is inflammation that will help. Continue to make sure you are drinking lot of fluid. Try to avoid coffee, soda and citrus drinks. But if no better, then do be seen.
Best of luck, and if you need anything else, please let me know.