Re: REALLY bad sudden neck pain...
Sounds like something that's NOT pregnancy related. One of the most important things I learned in my first pregnancy was to not assume my OB would treat (or even cared about) non-pregnancy related things. He just made a referral to another doc and let it be. Whether it was sinus issues or back pain, he referred me to a specialist.
So, call your OB's office on Monday and ask them to refer you to a doctor who they normally work with (unless you already have someone in mind).