Can you get a second opinion?

Where we live a local magazine sends out thousands of questionaires to medical professionals as to which doctors in their profession are the "Top Docs". I have switched doctors several times until I found one that could figure out my problems. And no, I am not looking for a doctor who will be a "Yes Man" -- I wanted to know if it was in my head or was I really sick.

Specific problem: Pulse Ox. My oxygen levels were above 90 in virtually every doctors visit.
I told them of my symptoms and each Pulmonologist shook his/her head and said there was nothing to support my observations. I bought my own pulse ox machine and started writing down the numbers, getting my wife to verify them. After doing this for about 6 weeks my pulmonologist sent me to the National Jewish Hospital in Denver, CO. My week of testing turned into almost 6 weeks and they found a tear in my heart, allowing the oxygen desat blood to take a shortcut through the Atrials, mixing with oxygen rich blood. Since the implant in my heart my breathing and oxygen levels have improved to the point I am consistently in the 95+ range.

Obvious Moral to the story: I did not accept the doctor's answer and took action myself.
NOW ... NOW when I say something is wrong, all my doctors listen and seem to go the extra step. Don't give up on yourself. Keep fighting, after all, YOU live in that body.
Good Luck...