Trapped gas in stomach?

Every so often I get trapped gas in my stomach. It isn't painful, but it's very uncomfortable. I constantly feel like I have to burp but it won't come out. Sometimes a little will come out but barley anything. It lasts for maybe an hour or so. It just feels like trapped gas. This happens every few weeks and I don't know/understand why. I take Beano food enzyme dietary supplement tablets which I think help with that? I'm not sure, do they? I also try to drink more water. Does anyone know why this is happening and what I can do about it? Thanks!