Umm, why do I think it's parasites?
Because I've seen worms as floaters in my eyes. I mean literally - an earthworm shaped thing that has been flicking around in my eye. I've had eye twitches for a few months now. I've got a 1.5" worm-shaped lump in my left ankle, which wriggles just under the skin (yes, it's house of horror time) when I apply malathion or hydrogen peroxide in that area. I regularly get rashes which exude white fibres. I have had a long shape appear on my left underarm which looked like a very long worm folded on itself 2 or 3 times to fit into that area. I've had headaches but they are non-generalised site-specific aches. Then they move, and a few hours later I'll have a blocked ear.
Maybe it's all in my head, but I think it's a worm.