Hi welcome to Health care magic forum. As you describe if it is missed in M.R.I. there must not be any thing successeptible. So i think your problem must be psychological, due to doubt that the injury
is so big and the M.R.I. is normal there could be some problem in side, or might be some or other worry causing these symptoms. Of course we cant deny that there could be unexplained problem in the brain, or cranium.
Any how you had the tests done you consult your doctor again for further evaluation of the case.
Besides i advise you some diet recommendations as avoid taking spices, chillies, junk foods and oily foods, as indigestion
can also cause all these symptoms.
Wishing for a quick and complete recovery and thanks for calling.