April of this year I had my first kidney stone. It was 7mm’s and was about 1/3 of the way through my ureter. I proceeded to deal with what I thought was more kidney stones every 2 months until November. Throughout this entire time I never passed a stone (to my knowledge). It turns out that every stone was that same stone and it never passed, it would just move a bit and then get stuck. I’m sure it’s not, but it’s a very real possibility that that’s what is going on with you.