At least I think it's heartburn. It comes in waves - an acidic sort of searing pain in the centre of my chest. It's been like this since Saturday. I have had gastritis previously so I had some omeprazole at home which I've taken daily since. Also gone through a bottle of gaviscon since yesterday but nothing is helping! When do I start to worry? I also have gallstones but that's much lower down on the side so I don't think that's the problem.