Hi: I have dealt with similar head pain off and on, though I've never had any issues with my eyes losing focus. I have had pain which feels like it's behind my eyes, though.
Have you tried one of those sinus masks which you microwave for a short time? It's sort of like a bed buddy, but just for the face. If you try one, make sure it isn't too hot (they heat quickly!). Even when I have any type of facial pain, not just sinus pain, this seems to bring a little relief.
Carefully using steam generally helps me with head pain, as does a gentle neck massage.
Since I've cut way back on salt and sugar, so far (hope it keeps on!) I haven't had a lot of these issues.
It does seem fibro-related, but you are smart to get a sinus x-ray and continue to have it checked out by a doctor.
I hope you get answers soon and things are much better. Best wishes!