You might consider talking to your cardiologist about the meds you are on, the dosages might need tweeking.
Sometimes probiotics and living yogurt (the kind without sugar, the label should give you that information) help with a sour stomach. Do you take your meds with food? That has helped me, even with some supplements.
Consider using stress reliving techniques such as deep breathing and meditation CDs (. Stress often increases stomach acid and pain. You don't have to dedicate a room in your home to relive stress, just a comfy chair and a willingness to let go of negative mind chatter for a few minutes.
Best of luck, take a nice walk while you consider that your body was created to heal itself.
AFIB is a serious condition, and it is good news for you that your heart is beating normally now.
Amiodarone is a very effective drug to get the heart beating normally, but it isn't so much a question if the patient will experience a side effect, its a question of which side effect. The big danger with AFIB is that it will result in a stroke, and the danger of stroke trumps the side effect matter...
I took Amiodarone after my AFIB issue following bypass surgery, and experienced eye and breathing issues, but it can cause many other problems. I've never taken Diovan, but think it is a powerful blood pressure medication.
I'd be persistent, and let your doctor know of your discomfort. I'm betting your drugs are causing your symptoms, and sometimes they can be withdrawn or the dose minimized without compromising your danger of a stroke.
Keep us informed.