A lot of woman develop gullstones in pregnancy and can be the leading cause to ongoing stuff after they are no longer pregnant.
But in the mean time, use gaviscon in chewable form or in liquid form. Tums are useless I had to eat two packs of those and it made a small improvement. lol
Or pepper as in black pepper, do some research on it, I am serious black pepper helps to reduce heartburn and indigestion. Milk may coat for a few minutes, but its actually bad to drink milk when you have heartburn, it ends up curddling in the stomach and comes back later.