Have you found a resolution to your burping problem?
I've suffered with similar symptoms for about three years. I've had a number of tests including an endoscopy. Nothing showed up. My Dr., in his brilliance, said I was swallowing air. I pointed out that this started almost instantly after I took antibiotics for Lyme disease and that it was unlikely I all of a sudden starting swallowing air. I was also given antibiotics about a year later for the possibility of a peptic ulser being the cause, but it did not help.
I can expect the condition to get worse after a big meal or one that has lots of carbs. The burping really gets going about 6- 8 hours after eating something like this. My wife comments that I burp alot dring my sleep. (Guess I'm still swilling down the air!)
Like with you, it continues to be a nuisance. During the day as I move around it doesn't seem too bad.
This has to have a logical medical explanation. Something in my stomach is generating an excess amount of gas. I'm surprised the discussion dropped off after 2000.