Hi jocca, I've been having kidney stones for the past three years and I formed and passed more than one.
I wouldn't worry, if I were you, especially since you had tests and have been followed from a doctor. What I think about your discomfort, which is very similar to what I often experience, is that it might be the so called "gravel" passing through your urethra. It means a number of tiny, not so painful stones that are leaving your body.
Are you following a diet and drinking a lot of fluids during the day? Let me know how is going but don't worry...anxiety doesn't help the discomfort