Yes stop riding that distance until you get the issue fixed. Obviously you don't have an average body. You have issues. No one here is going to be able to diagnose the issue without an examination.


Best thing to do is to consult an expert. Forget about going to the LBS. You need someone trained in sports medicine to help you. Specifically cycling. You can start by calling the sports medicine department at your local university. We have two fellows here are Pitt that specialize in fitting folks on bicycles.

You might also see your GP. He / she can determine if your pain is related to riding or it is some other issue that is becoming more obvious after you ride a distance. Meaning it could be a problem for you at some point even when not riding.