One of the characteristics of kidney stones is that you simply can NOT stay still. You pace and pace and move and move.
Kidney stones can be diagnosed through the use of X-Rays - I have never had an ultrasound to diagnose, and I have passed at least 10 over the years.
The pain is their moving through the ureter. You get the pain no matter what position you get into. If changing position or being still stops the pain, very unlikely to be kidney stones.
Drink, drink, drink lots of fluids (no caffeine in any way) to get them to pass.
The danger is that they will block and damage the kidney. Friend of mine lost 85% of one kidney function due to blockage.
I find that a hot bath helps, at least it makes me feel better to soak.