I am 16 and I used to have hemoplegic migraines... which is probably the most painful thing I have ever experienced. Basically, it is a migraine closely related to a seizure, and before the pain hits you, you start to see spots in your eyes and eventually go blind. My wrists and my face would become numb, and it cant be treated with imitrex or any other prescription migraine medication. These lasted 5-10 hours, and constantly puking from the pain the whole time. I have been to the ER twice for them, and had to get Demerol injections so that I could stop puking and rehydrate myself.
When no doctors could give me anything, I started smoking a few bowls here and there. The more I smoked, the less often I had these migraines, although I never had it on hand when I actually had a migraine. Realizing that it was helping I started blazin up as much as I could. I smoked a bit more than every other day and they completely ceased.
Afterwords, I figured out that stress, combined with a high sensitivity to light, was causing them. The weed relieved the stress and after I figured that out, I didn't even need it anymore. I learned to chill out when I was starting to panic, and now 2 years later I still haven't had one sinse then.
Basically, I can enjoy life now. Without marijuana I still would not be able to go camping or to theme parks or parties, or even get on an airplane. Oh, and thankfully it's not addictive...