I can strongly recommend Fitwerx. They are in Waitsfield VT and Peabody MA and they are excellent. They take every cyclist seriously, find out about your training and your goals, look at your current setup and where you think you are having troubles, and treat everyone with a huge amount of respect.

http://fitwerx.com/

Set up an appointment and plan to spend 2 hours there. Worth every penny.

BrokenSpoke