Hi, dictated, and welcome! I have never heard of anyone with fibromyalgia having this type of vision problem but that doesn't mean it can't happen. We do have an intolerance to bright lights and we have the pain and "buzzing" sensations. We have fibro fog and we have been known to walk into walls, dishwashers, etc. I googled "phosphenes fibromyalgia" and some information did come up.
I did google "phosphenes multiple sclerosis" and several sites did come up, too, so this does happen with some with MS but I didn't read it closely. Phosphenes might happen for other reasons, too. Like Gretchen said, your MRI didn't show lesions so you probably won't be diagnosed with MS.
Check out our Fibro 101 thread...the third thread on the forum. There are links about fibromyalgia including a list of symptoms. You just might see yourself there.
It does sound like your doctors are running all the tests so try to relax. They will get to the bottom of this. Meanwhile, ask all the questions you want. We are here to help you. Please let us know what they find out. I hope to hear more from you soon.
Sherrine