10 yr old daughter s symptoms are sneezing that clears her sinus cavities several times a day even though she has no congestion, drainage, burping, feeling of food sitting in throat or esophagus, nausea, hardness in stomach. Cat scan of sinuses showed very slight inflammation; upper endoscopy w/ biopsies & ph probe were all clear; scratch test for food & environment all clear. Allergy meds, Nexium, Prilosec failed to resolve symptoms. What might cause these symptoms?