It could be the acidity of your urine which if very high could be irritating your bladder or urethra. Get some urine pH strips from a drugstore or online. Be sure they are ones that track pH for urine and not blood. The urine ones are measured in very small increments. Test in the morning and see where you're at. If very acidic then,
1) use Prelief throughout the day
2) cut back on OJ, cranberry juice, or other acidic beverages
3) take
Quercetin
4) drink a lot of water - 8+ glasses/day - you can tell if you're drinking enough because your urine should be clear or near clear all day long. If it starts to turn yellow or dark yellow it's a sign you're dehydrated. Morning urine is the only exception to this.
For me, I didn't have to do any of this before CPPS. I think that once the nerves in that area get as over stimulated as they do with CPPS, even minor irritations that would have never bothered you in the past can now become a problem. The trick I think is to get your urine as close to neutral pH as possible.
There are also a series of books you can scan for at Amazon on the acid/alkaline balance in foods. Some people believe that much of our Western diet is too acidic and is the cause of a lot of health problems. And it's not always foods you think of as being acidic that are in fact acidic. I'm not sure about how far I'd go with this train of thought, but it might be an issue for you.
I'd start with 1-4 above and if that doesn't help, get one of those books and review your diet. Either way, getting to neutral (7.0) pH urine is key here.
Hope this helps
--MB
note: not medical advice, just my opinion.