My kub report said a "13mm calcification which could be a proximal ureteral calculus on the right side. how could that be with no pain andno symptoms?

Urinary stones: Urinary stones, even in the ureter, don't always cause pain. You should see a urologist to sort this out. You may need a ct scan or retrograde ureterography to know for sure.

Need eval: Kub is a relatively insensitive and nonspecific test for kidney stones. There are situations in which a stone is present in the ureter but does not cause major blockage and, hence, not much pain. With that said, a 13mm stone is quite large to be as asymptomatic as you describe if it really is in the ureter. The solution is additional imaging, most likely a noncontrast ct and urology referral.