Hi there!
I used to have episodes of really uncomfortable burping. They went away after I had my gall bladder removed.
Now, if I eat too much fatty food, I get the same symptoms (burping, gas, discomfort, bloating). I try to regulate how much fat I eat at a time. If I overindulge and get "the burps", then I take an OTC anti-gas pill (simethicone-- spelling?), and it subsides.

I have had a number of "cancer scares" in my life. Please don't panic about cancer. : ) A lot of symptoms of cancer are also symptoms of other, less serious, problems, especially in the guts, which can be really complicated-- or really simple (too much fatty food).

If you are worried, see a doctor. If the doctor doesn't seem to be listening to you, get a second opinion or even a third. Try to find a doctor that you trust, one who listens carefully. Medicine is still an art as well as a science. At some point, you just have to trust the scans and the doctors...But you can still be in the "watchful waiting" stage.

Once, a gyn literally laughed out loud at my cancer fear. She was right, it wasn't cancer. But I never went back to her. I now have a great gyn, who sees things from my perspective: There are reasons for my concern but I'm not a doctor, so she explains things to reassure me, and she doesn't laugh at me.

I don't mean to minimize your worry or to make any of this seem easy: It's hard to get the right "tone" in a short post. It IS scary when your body is doing strange things, and sometimes it does seem that the doctors aren't hearing you.

I have really rambled all over the place in this post- sorry about that! But I hope that sharing some of my experiences has been helpful to you.

Take care!