I have 4.5 mm kidney stone at the ureterovesical junction, and have bubbly urine in mornings. why? (renal profiling normal, no protein in urine)

Check 24h urine prot: "bubbly urine" usually indicates protein in the urine but not always. Sometimes just the force of the urinary stream can create "bubbles" in the toilet bowl. But your concern about protein in your urine is valid. I suggest you ask yourdoctor to order a 24-hour urine for protein since it is the most accurate way to detect protein in the urine.