If doctor says MRI with contrast "shows something" and makes appt for next day to discuss should I be worried?

Went in for headaches that are worst when waking in the morning. Have them most every day. CT scan caused MRI with contrast to be ordered. Now I'm scared. Doctor said it could be something that's been there since birth, but wants to discuss "next step". What are some of the most probable things that could have shown up?