You might be in the early stages of labor.
Oh, And I don't have any advice on the heartburn. Sorry.
From what I've researched beans and veggies can cause the gas and too much gas can cause back up in your digestive system to cause a heartburn. I would say try smaller meals, possibly avoid what you ate before/ test if that was what caused the heartburn, avoid lying down within 1 hour of eating, and have a warm beverage or soup after your meal (this tends to separate fatty foods that can also cause heartburn). Hope this helps. Praying you have a happy baby!