I get it now and again, its to do with all stomache been squashed and creating excess acid which will feel like a burning pain or yuckky acid sicky stuff!!!!
I find it worse at bed time, so i sleep slighty upright, also avoid spicy food late at night, before bed i have a peppermint tea or glass of milk which helps. If i get it during the day i will have a polo or something minty.
You can get stuff from chemist/doctor that is safe to take but i am trying to hold off on that till it gets really bad haha
Good luck xxx