To those with chronic UTIs: Make sure that each time you are told you have a UTI that a UA is done, because as stated earlier, it is possible to have UTI symptoms without having a UTI. It is called Interstitial Cystitis, or Painful Bladder Syndrome.
For those with chronic bladder pain/burning: IC is not caused by sexual activity, but sexual activity usually causes flare ups in symptoms. IC is not bacterial, so you cannot take a medication to cure it, although there are some medications out there that help to alleviate the symptoms.
My advice: Research IC. If you think you may have IC then stop all cranberry foods and supplements immediately. Cranberry makes symptoms worse. Although cranberry helps to prevent infections, it irritates the bladder tremendously for those of us that have Interstitial Cystitis making pain and burning much worse.
And if anyone needs more info or someone to talk to about the matter check out this anonymous forum. Its great for all kinds of issues, not just IC. dailystrength "dot" org
Good luck