Digestion/stomach pain?

Just wondering if anyone else has had this. I'm 8weeks5days with twins :) I've had no nausea or sickness but for the past few weeks I get what I think is digestion pain come and go. It's like pre-pregnancy when you have a bad tummy but this is actually further up (not in my guts). Kind of where I would expect heartburn, but it doesn't burn so I guess it's not that? It comes in short waves. Not awful but annoying that I can't pinpoint what it is.