Hi Missy. Have you gotten a diagnosis? Any improvement?
Does he have any symptoms during or after physical exertion - if so that would raise suspicion about heart problems. You specifically mention that he has problems after meals and at night (while lyign down?) -- the symptoms you listed are all consistent with GERD. In all cases of chest pain it is always best to get checked out by a Dr. (definitely go ahead and schedule an appt) to be sure but in the mean time there are some palliative measures you can take in the event that the source of the problems is stomach acid and in someone your boyfriend's age acid problems are a much higher probability than heart problems (look up GERD online - read about the symptoms, personal stories etc.)
(1) Try raising the head of your bed a few inches (ie - raise it up on blocks or books) - this way his head will be a few inches higher than his stomach -- essentially making gravity work for you to keep acid from coming into his esophagus/throat. In some people acid gets all the way up to the throat and can sneak its way into the air passages causing a cough, hoarse voice, chest pain etc
(2) Try to eat dinner earlier and wait several hours before going to bed. You could also consider eating bigger meals early in the day and a smaller dinner.
(3) Buy a pack of Prilosec - its about the strongest GERD med you can buy without a prescription - follow the directions on the package to take it once a day every day in the morning -- don't be frustrated if you dont see an improvement right away, the drug needs to be taken daily for several days in order to start working.
These ideas are all pretty standard and may help alleviate your symptoms if they are due to GERD - also, even if you try them and they don't help you'll have good information that will help your Dr. in thinking about your problems.
Best of luck!