I have gerd but prilosec doesn't seem to be doing enough. also doc said possible costiochondritis possible. what's best way to tell the difference ?

Esophagram, pH probe: If you are having persistent reflux symptoms despite medications, you should undergo EGD (scope in stomach) to rule out ulcer, etc. An esophagram will help diagnose reflux and other functional esophageal problems. Finally, a pH probe study is needed to confirm the diagnosis of acid reflux. These studies will help differentiate your pain from other sources.