I bought a bike recently from the best bike shop in town: Proteus Bicycles, in College Park (Maryland). Here is the owner, Jill, perfecting my bike's fit. So much of bike comfort is mechanics: how the handlebars are tilted, seat height and length, pedal position, etc.
This bike store has a cult following, people flock here from miles away. They only carry top-quality bikes and their staff are extremely knowledgeable and warm and friendly. How often do you see that nowadays? I highly recommend this place.