You mright have already had covid then. I’m a week from my.second Pfizer dose. My first shot kick in 10 minutes after injection , with chills then flushing to heat flash then chills again. On a every 2 hour cycle 30 min of chills feel fine then flush to heat for 45 min then fine went on for days nearly a week. My internal med guy is convinced I was exposed to covid and that is my body’s immune system in war mode to the already recognized vaccine proteins. I declined an antibodies test no need to spend the money since the second shot will convey immunity regardless. I broke my isolation bubble in the first week of January for patriot duty and that’s where I think I got exposed.
Could be. Your chills sound similar to what I’ve been having.
A year ago through much of January and February I was uncomfortably short of breath, especially at night. It didn’t respond to my asthma meds. I had a low grade fever and a painfully inflamed ear as well. This was maybe a month before Covid was known to have broken out in the US but I’ve wondered if there was mild variant already going around Southern California.