+1 for tendonitis and getting it looked at! seems like the only way i've ever gotten rid of it was to rest it, for a lo-o-o-ong time, and then it can always come back.
i know you've been fitted, but are you really comfortable on the bike? is there one position more comfortable than others (on the top of the bars instead of the hoods, maybe?) you should shift your hands on the bars often when you ride, from the hoods to the tops to the drops.
good luck as you try to fix this, i know what it's like, i totally feel for you!
laurie
Brand New Orbea Diva | Pink | Specialized Ruby
2005 Trek Madone Road | Pink | Ruby
1998 Trek 5200 Road | Blue | Specialized Jett
???? Litespeed Catalyst Road | Silver | Terry Firefly