What Causes Stomach Sickness And Mid Back Pain?

Yes I have bee sick to my stomach since late last night. No vomiting or dirreaha, had a little soup today but that and some 7up is it. Had the flue shot in August. My right mid back hurts a lot. I did tAke zertek for allergies and ompersol for. Gerd. I just recently took 2 Advil gel caps but I feel aweful