Swallowing back down sick, 5yo, is this reflux?

[Iamalmost40]

My ds is 5 and it sometimes seems as if he has had some sick come up in his mouth and then he swallows it. It's not a new thing and I have never been concerned but today he explained it to me. He said that "stuff is coming into his mouth". He often gets hiccups which I think is a result of his. Sometimes it does smell of sick, but I don't notice it a lot of the time.

Can anyone suggest what this could be? I have mentioned it to the GP before but they weren't really interested.

Many thanks

Does he burp first? My DC get this and swallow it and they do smell of sick when it happens. If they happen to be bending over, they might spill it down their tops/the carpet etc.. They have been on reflux meds (as definitely have it anyway) since birth and do also get a lot of hiccoughs - it is a common thing in refluxers. I can't say for sure, but thought that might help a bit.

Thank you, it is more of a gulp than a burp!. I have just had a chat to him and one of the other things he says is that he has had a really sore throat at night which is making him wake up and wriggle lots. Think I will go back to th GP next week.