Also drinking cold drinks or washing my hands with mildly cold water creates a systemic change, which makes my head hurt.

My wife had the same thing you do.  It took a while but a doctor at the emergency room thought it was neuropothy (sp?)  Her pain was bad enough where we had to take two trips to the ER and two CAT's.  Well, everything is fine now.  She has some pain every once in a while.  The miracle drug was.... TOPAMAX.  The wonderful nurse at Stanford suggested the medicine.  Our retarded insurance made my wife take something different for two months to no avail.  She suffered daily.  Then our insurance finally approved it and she is doing great now.  It took about 1-2 weeks before it started working well.  Good luck!!

   Aren't those "indents" actually the small holes that allow the temporal artery to still be attached to you scalp yet be placed on the brain and then come back out onto the scalp(sounds confusing,it' hard to explain....) If they didn't leave these, then you couldn't relace the piece of skull without cutting off the artery that is attached to the scalp,KWIM?Kathleen has two on each side,one a little above her ears and the other a few inches just above that,you can actually feel the pulse of the artery going into  her skull,then you can't feel it until it comes out the at the other "indent" just above it.I'm not sure if you all had the same "type" of surgery that Kathleen did.......Also her ehad is much more sensative since the surgery even now(5 yrs later).
Mary Grace