This is only my personal experience, YMMV and all that good stuff, but anyway:
Before I had my gallbladder attack, I had heartburn all the time. Now, maybe that was one of the symptoms of having a gallstone, I don’t know. But after the attack, I was told to cut way, way back on my fatty food intake, cholesterol, etc. FTR, I still have the stone in me; I won’t have the operation until February, so the stone itself doesn’t seem to cause any heartburn (for me, anyway).
Citrus fruits still give me occasional heartburn, but since I changed my diet so drastically, I’ve had virtually no heartburn.
Lean meats, lots of vegetables, plenty of fruit, lots of water, lots of fibre, and no more heartburn. Watch out for spices - they don’t have to be hot to cause heartburn, either.
I only drink water, green tea, a little milk (I’m lactose intolerant as well), and apple juice. Too much orange juice gives me heartburn. I don’t eat red meat and only eat lean turkey and chicken, no eggs, no oils, no peanut butter, that kind of thing. It sounds harsh, and even kind of bland, at first, but I’ve found all kinds of substitutions and I sometimes feel like I am not on a special diet at all.
Another trick is to not eat until you are stuffed. That can cause heartburn.
Anyway, I don’t know if any of this will help at all. It could help, though, to keep a close eye on fats/cholesterol, spices, citrus fruits, sodium, etc. Becoming a label-reader could help, but it might be a tough thing to stick to if you’re not motivated to do it. (Hell, my only motivation is the fear of horrifying, crippling pain - if it weren’t for my stupid gallstone, I wouldn’t have changed my eating habits despite the awful heartburn I used to get.)
Good luck.