A hiatal hernia is when part of your stomach bulges up into your chest cavity. Duodenal is the word that describes the small
opening to your stomach, in particular, the sphincter that closes off your esophagus. A small hernia may not even be noticed. A large hernia can cause you to have Reflux, the contents of your stomach moving up into your esophagus. Your doctor checked your esophagus to see if there was damage there, would seem he did not find any, that is very good! But you may often have heartburn, gas, and bloating.
See your doctor to find out what specifically is your situation. I know he will want you to keep stomach acid away from your esophagus. This can be done, if your lucky, by not lying down after meals for a few hours. If it is a bit more serious, you may have to restrict your diet of acidic foods. Whatever your instructions are, follow them! If you do not have Barrett's, consider yourself lucky! If you can control your condition with diet, consider it a gift. Many have to avoid almost every food you think of, acidity foods, tomato products (soup, sauce, paste) onions, garlic, alcohol, smoking, fatty foods, geez you don't want to know!
Some hernias have to be repaired with surgery. I've known a couple of people who have had this done, it's not very fun. Once you reach that plateau, surgery corrected stage I mean, then you will have to watch your diet for the rest of your life. Heartburn turns to gastritis, gastritis turns to Reflux, Reflux turns to Barrett's Esophagus, and Barrett's turn to cancer.
Find out exactly whay you have and what you need to do to control it, hopefully keeping it contained to it's present condition.
I went through the gambit with my Father, first heartburn, then double hernia surgery, reflux, then he had a hard time swallowing, Barrett's, then he began to lose weight because he couldn't chew things small enough for them to get down, then cancer.
Good luck to you, really nail your doctor to the wall until he tells you everything!