Can sinusitis cause a new prominent vein and bright flashes in that part of the eye sometimes when i tilt my head, and facial and head tenderness? docs weren't sure. if not, what can?

Facial/forehead tend: Sinusitis can cause facial and forehead tenderness and other eye symptoms may be coincidental due to infection.

That's a tough one: The light flashes are the thing that is confusing. We wouldn't expect light flashes from a sinus infection. Sounds like a migraine or a retinal problem. Have you seen an ophthalmologist? The pain when you tilt your head in the sinus area is something that's typical for sinus pressure. If you do not have other symptoms of sinusitis and normal x-rays look for something else. Migraines most likely.