A very stubborn friend of mine

has had a stiff neck for going on 3 days now.
It's not getting any better at all, I asked her to go to the doc but she's refusing

(women... NEVER listen lol)
Is there a reason why a stiff neck could warrant goign to the doc office?! I know some infections can cause stiffness in muscles but don't have the link to back them up :/
She can't turn her head at all without pain, although she says she can nod up and down OK
any help!?