Width and degree bend in the bars can have a lot to do with wrist and hand pain. This thread below was specific to mountainbiking but much the same stuff applies.

Not all alloy bars are made the same. A lighter weight bar may absorb more road buzz than another.

Your forearms, wrists and hands should, in relationship to one another, be as straight as possible in all planes. If you hold the bar closer inboard or outboard does it make a difference? If your brakes levers are tipped too far upward and you ride with your fingers out over the levers, you'll cock your wrists upward.

Also, are you using a death grip on the bars?

http://forums.teamestrogen.com/showt...ght=flat+width