I think Fyzzio makes a good point and in case of no improvement referring on to exclude would be a good idea. Having said that instability (definitely of C0-C2) could cause these symptoms as well. Swallowing: overactive platisma? Blurred vision, dizzyness, headaches? Overload from the neck? Raafox points out that MRI and scans have come out clear but it is not mentioned if the Scans have involved the neck thus possibly the brain is clear but not the neck. How about the jaw?
In principle the the symptoms as problems of swallowing combined with dizzyness and headaches could be caused by stress, hyperventilation, VBI and so on.