I have the signs of Gerd..just started taking Nexium 5 days ago. I have belching...gas...and pains that move around...i did the ugly episode of food kinda coming backwards a time or two.Here's my two questions?How long until the Nexium works or helps?And, how high in your chest can you get an ache from IBS or GERD?? I sometimes ache just rght of my breast bone, but only for a few seconds normally...its not my heart or lungs had chest x-ray and heart ekg and test where the inject die...both fine.