A bike fitting is a good place to start...
Pricing varies from shop to shop, so just give a good local shop a call and see. Figure on $100-150 for a complete fitting, though there may be less expensive alternatives depending on the shop and how bad your machine currently fits you. I know of instances where an experienced shop guy just looks at somebody on a bike, says the "xyz" is way off, and the only cost was the parts/labor to fix xyz. It wasn't a "fitting" when you're measured up and spend time spinning on a static trainer on your bike, but sometimes that is all it takes.
You'll find the good shops have guys that are pretty passionate (and quite dedicated like J @ Halters) to get your bike fit properly and helping you work though numbness/pain/discomfort issues. They seriously want to enjoy riding your bike, even if you didn't buy the bike from them.
They'll also be able to make suggestions as to what else you can do once the bike is fit properly and they can see you on it. Similar symptoms are caused by different things for different people.
Good luck.