I began a juicing diet 3 weeks ago and I woke up 3 days ago with horrible deep pain in my left knee. I've been doing a lot of research on the subject, in hopes of figuring out what I've drank that may be causing this sudden issue, and I just may have found the answer...
Google it. "Beet juice causes joint pain." You'll see what I'm reading. I had no idea that beets can cause a variety of problems in certain people. YouTube it too.
I noticed that you have beets on your list of things that you are juicing, so this could be the culprit. I'm going to eliminate them from my stockpile of juicing ingredients and see what happens.