Headaches and Memory Loss

This past year I had to the left sinus and into my left maxillary.  We were able to cut it out and with radiation I went successfully in to remission.  
But I am left with awful headaches (nerve pain) which will go into migranes (migraines) if I try to read or be on the computer for more then 30 minutes.  Most of all memory loss.  They gave me an MRI this past May which was clear.  No one knows why I am having these issues.  
Don't get me wrong, I am so excited to be in remission, but I can no longer work at this point with these headaches and especially the memory loss.  It is more short term memory as well as misinterpreting things (Almost like Cognitive skills).  Like looking at something (like a color and shape) then saying something totally off then what I just looked at.  My doctors look at my like a I am crazy!  
Has anyone run across this with sinus cancer treatment???