A simple test for intracranial pressure due to inflammation would be a round of steroids to reduce the inflammation. If it causes relief, the treatment is the diagnosis. Steroids are commonly used to reduce neural inflammation.

Blood pressure can also cause the pressure feeling. Checking BP when this pressure feeling is strong would be a good idea.

I believe everybody should have a home BP kit. Don't use the wrist BP systems. The upper arm systems are more accurate. Getting a baseline BP would be a start. Then, when pressure is felt or head ache manifests, the BP can be compared to the baseline. Adrenal malfunction can cause BP issues.