Hi, Molly! It's nice to meet you. I have a sister who suffers from headaches like you described, and she says they can be something. I don't know much about Chiari, but we do have a forum for Arnold Chiari Malformation. I'll post a link to take you there. Hang in there, Molly. There are a lot of nice people here who would love to help you any way they can. Good luck and best wishes!

http://neurotalk.psychcentral.com/forum71.html