I don't know how many of you have migraines, but it's near impossible to write through one. Even the painless ones, and yes there is such a thing.
They're almost like having a petit mal seizure but without the zoning out. Sometimes I'll see bright lights or shadows. Others I get vertigo so badly I have to lie down on the floor or crawl to keep from slamming into walls or falling over. The really scary ones completely mess up my ability to manipulate words. It's like how my dyslexia gets ten times worse when I'm sick or tired, only instead of making it just difficult to read or pronounce words, I loose the ability completely for several hours. I can't even bring the letters into focus or remember half my vocabulary.
They used to be rare occurrences. Then about two years ago, I started getting them something chronic. After several months on beta blockers to prevent and control them, I learned certain foods or additives can trigger migraines. It turns out the artificial sweetener I was using in my coffee didn't agree with my system, and switching to natural sugar had me virtually migraine free once again.
However, I've begun having them more frequently again. I kept track of them for several months and soon noticed a pattern. I was having auras and full blown migraines whenever CMEs or solar winds were hitting the earth's magnetosphere. The same is true for Mom and some other migraine sufferers in the family as well. (It's even a trend noticed and prepared for by hospitals, so I know I'm not alone even though it's not something that's been studied so far as I can tell.)
So what's a writer to do?
Other than keeping triggers to a minimum, there isn't much I can do unless I want to go back on a daily medication that causes lots of other issues I find just as troublesome. And I don't. I just now got my system back in order after last year's stint on them.
And on the plus side, slipping on a character and working through troublesome scenes makes for a good escape from the pain when they do come.