I hesitate to tell you my experience but am going to throw it out there because it never hurts to get it checked. The exact same happened to me, I finally ask the on call NP and was told it was an enlarged blood vessel, was put on heavy steroids, didn't help, so when my regular NP came back I explained it all to her ( 3 weeks since i saw the other one, 5 weeks since it started ) and she sent me for an MRI...the next day I found out I had a Brain Tumor , and 5 days later I wa sin surgery. They actually wanted me in surgery the day aftr but I had promised my children something and in case I didn't make it, I wanted to fulfill my promise, now, back to the same thing.and once again I have another brain tumor. Please get it checked if still in doubt.
your skin hypersensensitivty is migranehypersensitivity.
Try to avoid triggers especially glutamate (MSG) dont buy "ready-food""fast-food"
Migraine can be horrible, so I hope you're being treated by a neurologist specializing in headaches. There are many out there.
However, nothing you write about seems related to possible MS, so I don't have any suggestions there. But possibly your sore scalp is an offshoot of the headaches, which are caused by dilation of blood vessels close to the scalp.
Good luck,
ess