Welcome to NeuroTalk!
Headaches can be such a pain, I know, because I had them for decades, on and off.
I sometimes had sinus headaches and it sounds like that might be what your problem is.
I had to start taking allergy medicine in the spring and fall to help control those types of headaches.
I also had migraines for years and those were hormone related sometimes and also I'd get them from high blood pressure (which can be a serious condition).
Have you had a full physical aside from the MRI? I had allergy testing that showed my seasonal and environmental allergies.
I also take blood pressure meds to keep that under control.
Keep us posted on your MRI results and try not to worry!