I Have Been Experiencing Bubbles In The Toilet When I

I have been experiencing bubbles in the toilet when I urinate lately (maybe I have always had them...I don't know). I had a urine test as part of an overall health check up three months ago with no trace of protein. Yet, I do know I have a small kidney cyst. what is the difference between "foam" and "normal bubbles". SHould I be worried?