I have the same problem, and it is related to my acid reflux. You might want to get that checked out by a doc too. I was in pretty bad shape, and didn't know it. Now I run a risk of esophageal cancer. due to the damage that was done. like you, I just got heartburn a lot after eating, and especially when running or laying down. This would happen no matter how long ago I had eaten. The only thing that finally got me to the doctor was a sharp pain in my stomach that ended up being an ulcer that has taken the better part of 2 years to heal up. Mind you, I am only 33 years old right now.
(FBO) Cobb Stage 2+, AR Downpipes, Injen DCI, AA (Sport) FMIC, ER Chargepipe/Synapse BOV, Carbon fiber bits and Breyton GTS-R Wheels.