My doctor sent me to my LBS shop for a proper fitting when I had a numb hand after a ride. Can't say enough about getting a proper fitting!

When you go, wear your bike shorts, bring your gloves, as both of those will affect how your bike fits. Expect to spend half an hour (or more) on the trainer at the shop (you'll need an appointment for the fitting). Most shops charge something for this service, or you should at least expect to be charged.