Is Burping Inappropriate in the Cinema?

Yesterday I went to see a movie with a friend. I got ice cream. The ice cream was delicious but sat heavily in my stomach, creating a huge, painful bubble that I couldn't shift. Then, about halfway through the movie, I felt a big burp coming. I hoped I could just muffle the sound by putting my hand over my mouth, but it came out loud and gross, bringing up ice cream with it.

I felt bad, but it had to come out

The old couple next to me looked at me horrified, thinking I was burping deliberately to be rude. I said "pardon". That was all I could do. I felt more comfortable having released the wind, but a little while later, I felt another enormous burp coming. I knew I couldn't let out a big burp again like that, so I used up all my strength holding it back until it went back down to my stomach again. I then got bad pains from the huge bubble in my stomach and had to watch the rest of the movie feeling uncomfortable.

It's hard but don't I deserve to be comfortable

After I got home, I still had a stomach full of burp and ice cream, and felt sick, so I had some Andrews and then went to bed. The ice cream churned around in my stomach along with the fizz from the Andrews, and I freely let out some enormous, relieving burps that felt so much better and didn't bring up any ice cream, although I could still taste ice cream after I burped. Whatever I eat, I burp up, so it's not always easy to know what to choose to eat when at the movies. I've never thought about this before, but I think belching loudly in the cinema may be just as rude as belching loudly in a restaurant. My burps are always audible and I've learnt to live with it but it's still not always appropriate even though it is natural. I just can't seem to make my burps quiet.