In some of Dr. Patterson's talks (on YouTube), he says that "head fullness" is a common symptom of Long COVID. I wouldn't have labeled it "fullness" if I hadn't heard his term, but it might be that the "fullness" is what I call "distortion." Below are some of his comments that I transcribed:

[It won't let me post the link, but the YouTube ID is h2xyWiMS2Q0.]

Dr. Bruce Patterson, founder of IncellDx, in a presentation at
Georgetown University on Diagnosis and Treatment of Long
COVID, Feb. 2022 (at 35:30):

"The other thing is that the fractalkine receptor and binding
of non-classical monocytes results in angiogenesis through
VEGF, which of course we see in all four of these conditions
[Covid long-haulers, ME/CFS, Fibromyalgia, post-vaccination
long-haulers] and vasodilitation. Why is that so important?
Well, VASODILITATION RESULTS IN THIS HEAD FULLNESS THAT, I
WOULD SAY, 80 TO 90 PERCENT OF LONG-HAULERS TALK ABOUT. IT
CAUSES HEADACHES AND MIGRAINES. We think it causes brain fog,
tinnitus. It also causes, obviously, vasodilitation, hot/cold
insensitivity, low blood pressure which results in
compensatory heart rate increases. So you can account for a
lot of the symptoms in Covid long-haulers ... just by what
this interaction does on the endothelial walls. We call it in
a new paper, of course, "endothelitis," and of course we
intervene by using CCR5 antagonists, which prevent the
accumulation of these non-classical monocytes, and statins
which down-regulate the expression of fractalkine."