.....after I posted that, I see that you've been a member here for awhile!
Duh. So, you probably know your way around! Plus I think I've 'spoke' with you a few weeks ago actually! lol

The reason I'm asking about 'burning' pain, is because your post caught my eye when talking about that heaviness feeling. I know exactly what you are talking about.
I'm sorry you aren't getting any answers from the Drs. I know how frustrating that can be! Alot of us are in the same boat.

Part of my issue was because of becoming so inactive due to my pain issues (started in knees) and weight gain (from Lyrica, but have since quit that med and lost the weight), so the muscles in my legs became very weak (atrophy) which magnified my pain issues and it just seems to go in a huge circle of madness!
Does is hurt to climb UP stairs?
Do you hear a 'popping' noise in your knee (crunching sound?)