My mum has suffered from acid reflux for years, exacerbated by medication for high blood pressure but usually treated with gaviscon. She told me tonight that for the last month she's been noticing indigestion/heartburn when she is sitting down. It's not every day and she doesn't notice when she's up and about but she used to only really suffer when lying down so this is new. GP has tested for h.pylori which was negative and has prescribed omeprazole, I think. He still suspects stomach ulcer but can it be this if she hasn't got h.pylori? She has had a large fibroid for years (she's 70 now) which had been symptomless but GP's alternative suggestion is that this is now pressing on diaphragm as she has shrunk with aging. I think this sounds a bit 
but could it be that? Fibroid was apparently the size of a 5 month gestation foetus when she had scan in her 50s.
Basically I am concerned that these explanations are GP fobbing her off and am worried that it coud be something more serious. Could a stomach ulcer develop at 70 even with negative h.pylori? She says if omeprazole isn't making a difference he has offered referral for endoscopy. Any words of wisdom to make me less anxious?