Hi There, Whenever I Cough Or Sneeze I Get A

Hi there, whenever I cough or sneeze I get a pain in my left temple, this is generally worse in the afternoons and evenings. About 15 months ago I was a passenger in a car which crashed. There were no injuries at the time, but the car was my beloved Sonata. The pain only lasts for about 15 minutes at the most, generally only 5 to 10 minutes. I have had 3 MRI's - one with dye and two without and also one with dye on my spine. These show nothing wrong. Do you have any ideas.