My Wife Has Had A Sore Mouth, Tongue And Throat

My wife has had a sore mouth, tongue and throat for several months. No one has been able to diagnose the problem. She had an upper GI, but the results were inconclusive. She is taking Preacid for possible acid reflux, but no results yet. The GI doctor suggested the Previcid or Prilosac for 30 days. If no improvement, see a Eye Ears Nose and Throat doctor. Help!