Carbonated drinks can be a trigger, Dr Pepper use to set me off.
Also eating at the wrong times of day (too early or too late)

I suffered a lot from this and it got so bad I could not eat any of the normal trigger foods, tomato sauce, spicy foods, coffee to the point that they would not stay down. My doctor said it was gastritis and put me on Prilosec every day which worked fine but I don't like to be on medicines. I then started drinking Kombucha for all the health benefits and found that my acid reflux went away as well. I was able to stop the Prilosec and still eat all the foods that used to bother me. I find if I don't drink the Kombucha, I start having issues again.

I had what I thought was heartburn and it turned out to be my gallbladder. If the pain tends to be more on the right side and goes all the way through to your back, ask your doctor about checking for gallstones. I thought it was heartburn right up until I ended up in the emergency room with a blocked biliary duct. A few weeks later I ended up back in the hospital with an infection that led to its removal.

Gallbladder attacks come and go a lot like heartburn and they tend to be more common at night. I would be up all night with them.

Well, the actual surgery is not too bad as surgery goes. I'm thrilled to not have the gallbladder pain anymore. If your symptoms match, it would be worthwhile to look into as there are options other than surgery.

I've been feeling much better since it is gone. I think I've had low grade infections off and on for years (I've had mysteriously high WBCs at various times).