should the tooth go?

second molar from the back,  root canal & huge gold crown(only because all others cracked)  10 years ago.  For about a year now I have an extremely strong metal taste in my mouth eminating from this crowned tooth.  very bothersome.  Burning sensation even.  Twice, I have been to my dentist.  after xrays..he says he sees nothing wrong and suggested the metal taste was due to a medication I was taking.  He YELLED at me when I inquired about amalgam/ mercury issues.  He does'nt believe in mercury poisoning.  I also have an ongoing infection (ear or throat) for @ a year.  Sheould I have this crowned tooth removed?....and will my teeth shift if I do not have an implant to fill the hole?