Why might I have a headache since LASIK?

I have a dull headache in the back of my head since Lasik 6 weeks ago. I corrected for -8OS and -7.5OD. I had a flap lift 3 weeks in on my right eye and still have blurry vision in that eye. The headaches got worse after the flap lift. My corneal specialist says everything is healing fine. I haven't had stable vision yet so I hope once the right eye heals it will be better. Could this be refractive or neurological? I have no eye pain or discomfort, just the dull pain in the brain.