What Causes Persistent Headaches, Neck Pain And Nausea?

My daughter recently fell on some ice and landed on her tailbone. She has had a CAT scan and an MRI, which appear to be normal, but she is still having headaches, neck pain, and nausea. She has also had two massages. She is unable to attend her college classes because of the pain and nausea. Can you tell me what could be causing these symptoms, and suggest anything else she might try?