I get heartburn with my pregnancies (just waiting for it to happen again). Just like you, almost anything can trigger it. And nothing really seemed to stop it very well.
In the past, my TCM practitioner has given me a chinese herb mix for it - and while it tasted nasty as hell (I needed a chaser ...) it fixed the heartburn. The only thing that worked for me. I'll go back for more when I need to with this bub.
Good luck with it - it's not a nice thing to have.