Well you know my thoughts, Katie. Look at everyone on here who has said they have had this and they are still here.
Then there is the come & go element (I hope I doesn't get the spelling wrong there
)
When I had this, not being a HAer, I assumed it would be nerve or muscular. I knew someone who had a pinched nerve in the neck of how he described that with the pain so I went down the route of searching about nerve pain in the neck. I very quickly came across nerve spasm of the neck which explained it well.
There are exercises you can do for it. They helped. Here's the funny thing...just like your GP said it would go on it's own, mine did. 2 months on and I've not had it since after those 2 weeks.