Hi Fiacs,
not sure what you doc say, but there might be different reasons for your problem. One symptom of chronic prostatitis can be dribbling after voiding as well as urge symptoms and pain while voiding - it felt a bit like an UTI but isn't.
I found an interesting article in the net that deals about why Kegel might not be best advice in every case - not wondering that artice focus female - but the problem is for men the same and maybe even more important:
https://pelvicpainrehab.com/female-pelvic-pain/507/why-kegels-are-bad-for-your-pelvic-floor/. I'd learned that chronic prostatitis may lead to an overdraw pelvic floor what may lead to a downward spiral because that may also one reason for a chronic prostatitis.
To make the long story short - a specialized physiotherapist can find out easily if this is the case for you and also have methods to improve the things. So it might an idea to ask the doc next time about his opinion about this.
The floods may have a different reasons, because as far as I know the likeness for this combined with chronic prostatitis isn't that high. So you might be right wondering about that. Did your doc allready made a UDT / cystometry? If not it might be a idea to check that out just to make sure it's nothing different.