My doctor is a "fellow" in pain managment. what does that mean?

Fellowship: Fellowship is an additional year or two of training in a specific field.

Has extra training: To be a fellow in pain management means that your doctor has spent a period of time in the study of pain management and has passed exams demonstrating special competence in that specialty.

A jolly good Fellow: Doctors continue training after medical school for 3-6 years depending on their final choice for a career. After that they take on a position as a fellow in training and after 2 or 3 years take an exam on the field they have studied. If they pass, and most do, they become "fellows" - letting everyone know that they have successfully completed a tough training program.