4 wks ago CT show stone 1.5cm from vuj - 3 weeks with no symptoms but last 3 days I get bad bladder ache & urge to urinate - will stone pass soon?

It should. You did not mention the diameter of the stone but if it was 1.5cm from the UVJ if was probably small enough to pass spontaneously particularly that you are on tamsulosin.If the pain becomes worse you should contact your urologist and she/he can extract it endoscopically.Cystoscope goes through the urethra and you will be asleep.You shoud be straining your urine so the stone can be analysed.Be well.
Stone. That size stone is big to pass thru. Force fluids to 4-5 liters per day. An ultrasound is helpful. Your symptoms suggest the stone may be stuck in your urethra.