Could Dryness In Mouth Be Due To Muscle Spasms At The Back Of Neck?

HI, Looking for help here. I was rear ended at 35mph, neck not supported by headrest at impact as I was leaning forward. By next morning back neck muscles were burning badly. Within a few days noticed that neck was cocking backwards when asleep, eventually videotaped myself during sleep to confirm. Also began experiencing that my salivary glands would completely shut down when asleep. I would sometimes have extremely severe events of mouth at night that I knew caused cell and taste bud damage. The quality of taste over the last 10 months has diminished. When I have a severe dry mouth event, it can sometimes take a day or two before mouth recovers. The reason for this probably is because only certain salivary glands that function at night produce needed beneficial enzymes. What made the dry mouth worse was that my back neck muscles seem to contract significantly when asleep, thus obstructing my airways, further irritating the problem, which seems to mimic snoring symptoms of sleep apnea, but I am certain its the accident that caused the muscle spasm-ing and as a result the somewhat obstructed breathing passageways. Pain symptoms at least have eased some with recent acupuncture treatment, so maybe that will bring further relief as time passes. Was also prescribed Evoxac which I take only when I go to bed, which helps increase saliva when needed. However I ve noticed some decrease in effect in the few weeks I ve been on it. The thing is, I know these are just symptoms of an underlying cause, and I need to try and isolate the cause. My doctors haven t had any ideas. Have recently learned from my own research that the Parotid Glands salivate mostly when you eat & while awake, but that Submandibular and Sublingual Glands produce the majority of saliva when at rest/sleep. This leads me to believe that the problem is mostly with the latter glands, or whatever nerves trigger them to activate. Would be most appreciative in helping to understand what mechanism from accident is at work that would have caused salivation glands to cease functioning during sleep only. Such as which parasympathic nerves or glands might have been damaged during accident? Or, as a result of the muscle spasms I experience at night, what impact could they be having on same parasympathetic nerves or other glands? Where do the signals originate that tell the submandibular and sublingual glands to produce saliva when at rest? Knowing this might help isolate the cause of the problem. Thank you for any help, your ideas will be appreciated. Doctors are at a loss and I m becoming frustrated. Dave