Can focal pain in your head due to vigorous head-shaking mean a brain tumor. i recently read it in a medical book. going to neurologist but scared.

Very unlikely: If you already feel you know how you injured your head, it's very unlikely this is a brain tumor. I'm glad you have the insight to know that many of your health worries are unrealistic, and often people like you are helped by psychotherapy. Often folks like you have been through difficult lives and guidance on gaining new skills and ways of thinking can make all the difference.