No, it's not in your head. However, the frustration of dealing with an arrogant, uninformed neurosurgeon IS currently in your head (brain). After I had successful surgery with Dr. Feigenbaum and was able to return to work, the doctors hired by the state workmen's compensation board still insist it was "all in my head".
I'll say it again: If you have symptomatic Tarlov Cysts, contact the office of Dr. Feigenbaum and request a consultation. Don't waste any more time. And yes, trauma does cause this condition. It can not be confirmed whether the cysts were pre-existing, as most of use do not have spinal MRI's on a regular basis prior to experiencing the trauma.