Has anyone ever gone to mayo clinic?

Hello All.
I got back a few hours ago from my doctors. I went in today for the results of my MRI. I wasn't expected anything new, since this is the 2nd MRI of my left knee. Again, normal results. The pain is getting worse. The doctor basically told me I just had to deal with the pain. That I just need to move around more. Even suggested that I walk 2 miles every other day. Though I can't stand up long enough to take a shower..but sure I'll walk 2 miles, I'll get right on that..anyway.
It was suggested to me a while ago that I look into going to a mayo clinic. I'm under the impression that mayo clinics are a place where you go when you can't get a diagnosis anywhere else? I called and set up an appointment. It's going to be about a 6 hour drive to get there. But I'm doing it.
Has anyone had any gone to one for joint issues and gotten a diagnosis? Am I wasting my time? Should I be going down another route? Any ideas what I should do next? Any advice at all? I'm at a point now where I'm putting all my money on this mayo clinic because I have no ideas left...