What Is The Treatment For Dry Mouth And Throat And Discomfort When Swallowing?

I normally sleep on my stomach. However, it gives me a stiff neck. My chriopractor suggested trying to sleep on my back. So last night I forced myself to fall asleep on my back. I woke up in the middle of the night with a very dry mouth and throat. I drank two full glasses of water but barely felt any moisture. Today swallowing is uncomfortable, but not painful. I have no other symptoms. I am scheduled to fly tomorrow, but dont want to if i am getting sick. I am not sure if sleeping on my back, breathing through my mouth caused my throat to dry up to the point where it became irritated, or if I really am getting a sore throat. Your advice is greatly appreciated.