Don't know if you saw my posting below, but it sounds like we are in the same boat. I am 24, active, and have never had digestive problems. However, I was diagnosed with GERD three weeks ago because of chest pains.
It just came out of nowhere, and I think these early stages are the scariest because you don't know what the pain means or where it is coming from.
I have done a crap load of research and I suggest you: read up on GERD, know about the tests that can be done, learn about the drugs, and begin with preventative activities first (raising bed, eliminating caffine/fat/citrus, more exercise).
I am on lansoprazole and it has helped with the pain, but I am still uncomfortable most days. Little twinges of pain here and there. I am currently waiting for several test results (H. pylori, manometry), but am already thinking about surgery...because I will NOT put up with this
Don't worry tooooo much though. Things could be worse.