What Causes Sudden Sharp Pain In Neck?

in class i shook my head to get my hair out of the way and i had a sudden sharp pain in my neck to my head i went to the doctors (medhelp)and they checked my blood pressure balance heart eyes and reflexes and even strength and i wass fine but im afraid its somthn on the inside.i freak out when it comes to this stuff i wanted to know if its anythn to worry about