What causes sudden collapse followed by temporary paralysis? I experienced severe back and chest pain, along with a headache, followed by a sudden collapse resulting in temporary paralysis. What happened to me, and what should I do?

You. You need to see a doctor right away. I am not sure what it was, but there are some very serious things that can do this. I would be worried about problems within your blood vessels like clots or adissection. If this has happened just recently, and you cannot see a doctor very soon, you should go to an emergency room. If it happened more than a month ago, you probably don't have to go to the er, but should still see a doctor soon.
Stroke or heart atta. Need to be evaluated so you get treatment or the next time may not get up to tell about it.