I use the inverted commas because this injury, strangely enough came about as a result of using a different pillow and waking up one morning with my head and neck in such an uncomfortable position I could hardly move my Noggin for 10 minutes or so, I have had neck pain ever since.
The Doctor thought this could be a factor in my balance issues.
Am I right to assume that your Doc felt that your neck injury could cause bad posture, thus affecting the way you balance your head and hence influence overall balance?
If the above is the case, you could always buy a book on Alexander Technique. It's controversial as the results are tricky to quantify, but other members here have benefited from it - try a search.
Something I came across that's interesting is the work from Dr Galiffa in Italy (try a Google). Galiffa has pretty good credentials, and his book (in Italian - no English version yet, annoyingly) is all about sleeping posture. He believes that bad sleeping posture can put pressure on the jaw, potentially unleashing a Pandora's box of vestibular / audiological issues, such as tinnitus and balance problems - to name two. Galiffa has a book to sell, so be warned, but his ideas are interesting IMHO.
Stilton - do you sleep on your front?