This could represent a neuralgia (irritated nerve) which can cause intermittent severe pain. You could ask your doctor about this possibility, and also ask if an MRI of the brain to exclude structural abnormalities in this region would be reasonable. Also, an MRI of the cervical spine to exclude "pinched nerves" would be reasonable. A consultation with a neurologist may be helpful to better define the area involved if your doctor does not feel comfortable with the evalaution. Good luck.
Could this be in the area of the pituitary gland or the hypothalamus? If there were harm to one of these, how can it be determined?
Now, I would not suspect the chemical I mentioned unless you have many, many other symptoms going on at the same time: fatigue and a whole lot more.
They've also now found some other problem - with my nerves - too that I've been suffering with, so I would say not to be fobbed off, make sure you get this looked at because it's not funny to have it lasting longer than necessary.
Needless to say, it didn't help him. In fact it hurt him, as now he (who needs to avoid any and all chemicals) now has to take medication for the effects of the 'procedure'
He said it did no good.
In his case, however, he was poisoned from the solvent in gun cleaner and jet fuel: 2-butoxyethanol and that does cause various central nervous system damages and endocrine system damage and BLOOD damage (that will be where the commonality of provable harm is: premature destruction of one's red blood cells by the immune system, most likely) do a retic ratio & CBC with differentials. Ask for the size and shape of the red blood cells and do the white count by microscope, not computer. Check kidneys and liver, which this chemical targets, too