Welcome!
I did find this short reference to CCFs by our colleague Madere from many years ago – before John or I joined this forum: Carotid cavernous fistula - #2 by Madere_dancermom
Where posts on the forum are before 2016 it is much less likely that you’ll find people still active here, as we moved platforms in 2016. The involvement of the sight seems common with your experience, however. I’m a DAVF patient myself.
It does seem like a very good idea to get checked out by neurology or neurosurgery: a strong pain in the neck is often enough a sign of danger, so get checked out promptly. If in any doubt, go to A&E.
Feel free to ask anything of us that you’d like. You don’t necessarily need an exact match to your situation to find common experience.
Very best wishes,
Richard