I am hoping someone else can relate to what I am thinking and hopefully provide some insight.
Since a long craniotomy operation 3 years ago which was to fenestrate a cyst which was squashing my optic nerve I have noticed that I catch more colds despite a healthy lifestyle and supplements and the two times I have had flu since the operation, including a recent one ( not Corona) I have suffered headaches like I never had before in my life, they are so painful I went to the hospital the last time but within 24 hours the intense pain was gone with no treatment.
My gut feeling is that my immune system has changed and works differently ever since my head was operated on.
Another not good experience this year was after having the pneuma vaccine I had chills and headaches for a couple of days every week for nearly 6 weeks.
If anyone else has noticed a similar change in being able to fight viruses and headaches I would be happier knowing that it's not just me.