Re: what does a pain behind the belly button that get worse when I urinate mean?
Have you noticed any tenderness in that area when touched? Or any type of lump or bump either behind or directly above the belly button? If so, it could possibly be an umbilical hernia. They are actually quite common and many people have them from birth and never know it until something causes them to "surface".
I don't know if there's really a specific known cause for them, and most often the doc just takes the wait and watch approach. The symptoms often come and go and many never get any larger or any worse. Many women have them pop up after pregnancy, because the baby pushes them forward. My hubs has one and his was most likely because he had gained and then lost a lot of weight (especially in the belly) and the same thing happened. His will hurt a bit every once in a while. Then it goes away and so on.....
It could be a UTI, as neveragain said, too. Either way, it probably wouldn't be a bad idea to make an appt. with your doc. Best of luck and keep us posted, OK?