Gastritis Nexium Question

Long story short, 4 years ago via EGD I was diagnosed with E.E and subsequently functional dyspepsia after complaining of consistent stomach aches after eating that were made worse by movement and bending and made better by chewing gum and sitting up straight. This has remained the same, however been magnified recently.

Now, as of 3 weeks ago, I was diagnosed with an organic disease in severe gastritis, a hiatal hernia, and continuation of E.E after my symptoms became magnified. The doctor prescribed me to take 40mg of Nexium twice a day to combat this (H. Pylori negative). However, given that is a huge dose and the ween of period necessary for PPI's, I have been hesitant to take this dose and have only take 20mg of Nexium twice a day.

Since taking Nexium 20mg twice a day, I have seen the gurgling, burning, confusing hunger, and acid reflux go away for the most part; however, I am still experiencing stomach issues possibly related to the functional dyspepsia diagnosis (Fullness after certain meals, general stomach ache after all). Would it be smart to take the doctors advice (dumb question right?) and take the full recommended dose even though I feel as if my acid concerns have been taken care of?

Also, as a side note, can anyone possibly explain why chewing gum (while I'm chewing it) can sometimes significantly reduce stomach aches?