I learned how to not aggravate the knee (not as easy as I would have thought) and now the issue is disappearing rapidly. Full movement and strength notwithstanding. That should come about naturally as I'm active all day every day.

Good news. Did you figure out if it was knee or hamstring or ?

Oh it's the knee. I'm no physical therapist but keeping the knee from being stressed seems to be the key. I used to wake up at night having slept on my shoulder in a lot of pain. You'd think the body would wake you sooner.