Have the report sent to his primary care doctor and ask him what the question was. Or get a copy of the report and see what it says. If you don't understand, we may be able to help here if you type it out. Chest x-ray reports are very short.
They can't know that it's heartburn with just an xray. If they didn't do any other tests.......then your husband needs to see a Gastroenterologist for a complete evaluation. He also needs to see a Cardiologist just to be on the safe side. My father thought he had indigestion and was on his way to the pharmacy to get medication for it......suffered a major heart attack while driving with my mother in the car and they both died. I'm not trying to scare you but be proactive with getting him to see the right specialists. I wish you both all the best.