Your doc will ask you about you're symptoms. My experience with GI docs are that they know what the symptoms are of GERD and if you're symptoms don't match their knowledge, then they will seek other avenues. It seems that Prilosec is the standard med they give out for chest pain if all other tests are negative. Years back I had unexplained chest pain and they put me on Prilosec. It never stopped the pain, all my tests for GERD were negative but they still kept giving me the medicine. So, If the Aciphex is working for you, then you probably do have some heartburn. These meds don't stop general pain unless stomach acid is involved.
If they suggest one, an endoscopy is a snap...much prefer it to any of the other tests done for GERD. The nurses will prepare you and they may give you something to calm you down..it depends on you. Next thing you know you will be talking and they put the mask on you and you fall asleep...it takes about 5 minutes for the doc to put the scope down your throat and look around and you're done. It will take about 45 minutes for you to wake up and you go home...the doc will have instructions written for you indicating what was found....it's a simple procedure that doesn't hurt.
Good luck, don't be scared...we are a great support group on this site.