I have taken it without any taste side effects...that's weird.  I would try the mentos if you like them.  My Mom had the same metal taste when she was on chemo and gum helped her.  On the MS I would seek as 2nd opinion.  My daughter at 19 had her first incident 2 years ago.  Her right side became completely paralized and was confined to a wheel chair.  With therapy she is 99% back to normal and you wouldn't know what she went through.  The Dr. put her right on the Copaxone 2 weeks after discharge.  She has relapsing remiting MS.  With MS there is not a single test to diagnose it....it is a process of elimination.  She hasn't had another flare up and had to get off the Copaxone because of side effects.  She is now on a experimental drug study for the last 9 months. (A pill) This website is very good and might have your answers on Lunesta. 
  http://brain.hastypastry.net/forums/...play.php?f=195 
Good Luck!!