I can tell you what mine feel like, if it's any help.

I don't know if they're actual true 'headaches'. Basically... they sit in my left temple, and they rarely let up. It's awful. They can progress into a burning pain that runs from the top of my scalp on the left, down to my left eye. Sometimes into my cheek as well. Just depends.

Clonazepam has been the only medication I can tolerate that 'breaks' through the burning of these (I take a small amount of Clonazepam). I had terrible side effects so far on other options, such as antidepressants and anticonvulsants that are traditionally used to treat this type of pain.

As of today, I have a bit of burning, in fact, some slight little sharp twinges of 'electrical' pain in my cheeks off and on, but the headache is another matter. It's sitting up there brewing. Right now it's dull pain in the left temple/into the cheek, but I can feel slight burning at the top of my head starting up.

I try to avoid medications (over the counter or otherwise) for as long as possible when I get these headaches, but as you mentioned, these can last for weeks on end, and each day can be different. I also don't truly believe them to be headache or migraine... more MS having it's sensory fun on me