What Causes Nausea, Tightness In Jaw And Headaches?

My sister has had issues with nausea, tightness of her jaw and headaches for many years now. She claims that it was compounded with the birth of her youngest child. That would be nearly 4 years ago. Recently she has been going to a physical therapist and he claims that her issues have to do with a fall in her childhood, over 30 years ago! I find this to be a very suspect claim. What do you think?