groin ache and warm butt

Hi,

For about a week, there's a constant pressure ache near or at where my prostates are.  The ache is similar to having ejaculated 2-3 times within an hour.  When I'm sitting my *** feels like it's heating up.  The pain is just under my scrotum between the two sit bones.  Sometimes I feel an ache deep within the base of my penis.

My urine flow seems normal though.  I do have a problem with a sudden urge to pee after I get up but that's been like that for a few years.

I also recently had a sexual encounter about 2 weeks ago with an escort.  I hope it's not related to that.  Could it be UTI?  Or something worse which I don't even want to mention?

The pain is there all day and is worse if I do anything to reduce the space down there (such as flexing my stomach muscle or lean into my pelvis).