Was diagnosed with 3mm uvj stone three weeks had pain for three days and then stop. havent had pain since. could i have passed the stone or it hasnt continued to move?

I assume you're not straining all your urine to capture the stone so its type can be identified by the laboratory. Many patients do pass tiny stones without noticing them in their urine. If you don't want to have another U/S & If your current urinalysis doesn't demonstrate red blood cells in the urine on microscopic exam of the sediment, this suggests stone had been passed.