I do have the grainy vision too. It's more just when i look at the sky or at the TV and computer. The circle ones could be floaters. Those are totally normal. I think if you talked to everyone on this site they would say they've had them. What head pains are you talking about? At the moment I'm having a head pain that shoots down to my neck. I've been really tense lately, and i start classes back up tomorrow so I'm linking it to that.
The head pains are just random dull pains around different ares of the head. They don't last long.
your head pains are probably nerve or muscle related due to anxiety or stress. Keep in mind that the brain doesn't have any nerve endings so your actual brain cannot be hurting. if you were having an aneurysm or something severe the pain would be intense and accompanied by other symptoms. Nothing is wrong with your head, I promise.
let us clarify the difference between floaters and visual snow.
Floaters: are totally normal and everyone sees them, and yet again it is a question of awareness, because almost everyone has them and mostly we don't notice them. They can look like transparent lines or circles...like germs, or they can be little grey areas that move around when you move your eyes. Floaters are from the vitreous gel behind your eyes. The gel breaks off and you get these little floater things. Sometimes they'll go away after a while.
Visual snow: seems to be slightly different for everyone experiencing it. it is mostly characterized by static that covers the entire field of vision, and can include flashes of light, little spots of color, after-images (looking at your room and then looking elsewhere and seeing a faint, polarized image of what your were just looking at, or seeing a bright light and having an image of where that light was resting in your vision for a while) and trails (seeing something in movement, like moving your hand and seeing a ghost image of your hand slightly trailing the actual movement). Causes are unknown, and some people are lifers, while others develop it concurrent to anxiety, or after using a lot of hallucinogenic drugs. Some people say it is a psychological thing, other say it is a vascular thing related to ocular migraines (which i've also had and it's not the same). It is a big-0104 mystery to most medical professionals, and while it often makes me really anxious even though I've had it all my life, it has helped to refer to it endearingly as SPARKLEVISION, as an enhanced and more interesting perception of the world. Things become a lot less scary when you own and de-villainize them.
I've had the whole gamut of tests: MRIs, CAT scans, EEG, any poking and proding that an ophthalmologist is legally allowed to conduct. Nothing is wrong with my eyes or my brain, and I'll wager that nothing is wrong with yours either. If you have it, you have it. and you won't go blind and you won't die, it will get better and worse and better again, mostly based on your awareness of it.
Hope this helps a little. :)