What actually happens to our brain when we have a migraine?

what actually causes migraines?
what causes the weird symptoms? - e.g when i have one, my vision starts going weird - i have a flickery patch in my vision, i sometimes have difficulty speaking and my words get mixed up, everything seems really loud, i have weird sensory problems - my arm and hand doesn't feel like my own (hard to explain), i have severe pain in my head, then the next day if i turn my head sharply, i get a sharp stabbing pain in my head.
is there any way we can prevent migraines or make them less bad when we have one?

please answer in fairly simple terms if possible - i'm only at GCSE level! :)

thanks in advance

There are many theories concerning migraines, but the one that is most accepted right now is the vasoconstriction theory.

The blood vessels in portions of the brain, for whatever reasons, become abnormally constricted, allowing very little blood into that part of the brain. The neurons become distressed from lack of oxygen (ischemia), and are unable to maintain their normal electric gradient (resting potential), causing a gradient loss (depolarization) that spreads gradually from the center of the lesion.

The distressed neurons start releasing inflammatory signals (cytokines) that makes the blood vessels dilate again, but at the same time, the cytokines also increase the permeability of the vessels, allowing fluids to leak out of the capillaries into brain tissue (edema).

The dilating of the vessels and subsequent edema are what really causes the pain in migrains, so some drugs used in migrains attempt to stop this vasodilation process (Tryptans and ergotamine), while NSAIDs like naproxen or opiates like morphine are used to stop the pain. Most over-the-counter analgesics don't work on migraines, as you probably already know :(

I and my family are also plagued with your described affliction and our head will be sore several days with a severe one. I have been misdiagnosed as having a stroke. We're told blood vessels constrict by the medical profession. There is a doctor online named W.C. Douglass. Ask him, he is very helpful....james p.s. hope you the best

well what normally happens when you are having migraine is that your brain is trying to tell you there is something wrong with another part of your body.
so if you have an internal problem and it cant tell you by causing pain the brain tells you by causeing you pain

I was told by my doctor the blood vessels in your brain constrict that is why you have all of these symptoms, there is no way to prevent them you can get medication from your doctor to help relieve the pain.