In 2007 I was told I had a lesion on one kidney & a cyst on the other. Since then I never followed up on it, nor was I told to. If anything was to come of that, would it have done so by now?

Unknowable. This is a problem that necessitates a face-to-face meeting with your doctor. This will allow him/her to examine you, ask specific questions. And possibly order tests to find out what's wrong and what to do to help you.