I had a few splitting headaches along my journey, too.

Could the eye muscle problems be involved? I had ptosis,and had to wear an eyepatch for a while because of mine.

Head / neck muscle tension might also be a possibility. Those are some pretty involved muscle groups, and keeping your head in the right position with sets of muscles fatigue-ing out could result in tension headaches from (mis)using subsidiary muscle groups. The head is a bit heavy and we rely on it for a lot of stuff, so the muscles supporting it get a serious workout.

I got sidelined from driving a company vehicle because I couldn't move my neck. I was moving my upper body to look in the mirrors.