As pointed out in the STD forum by auntiejessi (correctly), it's nearly impossible for this to be an STD. More likely there's some type of prostate issue. Not sure why your testicles would hurt, altho sometimes prostate issues CAN cause that. The only other thing I can think of was if when getting the lap dance, your testicles were somewhat compressed by her sitting on you, but I rather doubt it. Just relax & rely on the Dr's test results & diagnosis...
I don't think anyone can offer more here since you've considered this a sexually transmitted concern. I'd stick to that forum.