Hi Cheryl;
Oh, it hurts to read of someone suffering so! I'm sorry...
Another person never really knows the extent of another's pain, or, their pain tolerance, but, it sounds like you're 10+ on the pain subjectivity scale.
From what I see in looking around the web is that head ache after GK is not uncommon.
So; Re, Drs, can you self refer yourself to a neurologist, pain clinic, or even neurosurgeon outside your radiation provider?
I've heard low dose Elavil, say 25 mg, can take the edge off pain of different types. Cheryl R. mention the nerve pain agents as Neurontin or Lyrica. But; The Dr, of course, holds the power of writing the prescriptions.
When you mentioned pain like that, I immediately thought the trigeminal nerve may have been irritated during the procedure.
Trusting you went to a reputable clinic/hospital, I'm trusting there was no treatment error. The GK is pretty potent and has the ability to produce even an AVM, or conversely, treat an AVM. Those tiny bleeds or jumble of vessels can cause great HA pain!
Gee; I wish I could help here with words. You may need a narcotic pain reliever if nothing else works. One thing about any of the OTC NSAIDS as Tylenol, Motrin, aspirin, Advil, is that they can produce rebound HA if overly used. They are also not particularly organ friendly and aspirin, stomach irritation or blood clotting friendly.
But; Finding a Dr. to see you immediately. Not sure where you're located, but I'd sound desperate to many and maybe make an appearance at a large emergency room.
Hang in there Cheryl. There are a lot of people here who know suffering and are at least with you in word and spirit.