I had a similar thing but more pronounced -- turned into constant burping. I strongly believe in my case it's helicobacter pylori.
After getting totally fed up with it ended up I did a "juice" fast for 3 days, actually drinking only water, and then when everything was good and empty out of curiosity tried barfing up a little stomach acid to see the consistency, amount of mucous, etc. A little came up, but surprisingly was not acidic at all. I thought that was weird. A common approach with the naturopathic crowd is to introduce vinegar into the diet, amongst other things like teas and coconut oil that I'm not sure are totally useful. (Google ACV for more on this.)
Decided to try at least the vinegar so I slowly drank about 6 ounces of organic apple cider vinegar yesterday morning on that empty stomach, which was totally nasty and for a little while turned my tummy into a knot, but within 15 minutes finally the burping ceased completely! What a relief. And in a few hours it made its way totally through my GI tract. Based on what emerged it apparently cleaned out some fats along the way. No water, nothing else, just a really good dose of the acidic vinegar and patience. Had to stay in bed for those few hours, just rejoicing that the burping was mostly gone, and trying not to barf since it took about an hour for the vinegar to finally continue through the pyloric valve into the small intestines. Really weird sensation when it made it that far and the body started to absorb it.
I let that sit another couple hours and by this point I was really hungry. Seemed my digestive system was ready to try restarting. Thankfully was able to eat the first "real" meal I've had since this all started. Before I was only snacking through the day and then dealing with the intense burping. Now I got a good-sized meal down, with my throat still sore, and everything went along fine. Just for good measure I added a fair amount of vinegar at the end to make sure my stomach stayed acidic enough.
At some point I'll do the breath or stool test for H Pylori and see if it registers.
Probably a H. pylori infection of your stomach. Have a breath test for H. pylori.