Cysts in kidney's

I had an MRI done for pain in my back and also an MRCP for other pains. I was told I have some cysts in my kidneys. These are the findings:

1.4 cm cyst within the lateral right mid kidney.
8 mm cyst in the right upper pole.
Approx. 1.5 mm cyst in the upper pole left kidney.

My Dr said there isn't anything to be concerned about but I can't help but worry it's something more serious.

Should I have them checked by a urologist or is this something that is nothing to be worried about. How will I know if they get to be more serious? Do they cause pain or bleeding?

I've never heard of this before and don't know what to expect.

Thank you
Celia