Well, my arm is sore this AM mostly when I do a lateral raise. Same for my wife. And since I have food allergies, I had to hang out for 30 minutes versus 15 minutes at the vaccination site - no problem. And I moved my arm a lot while I was hanging out. My arm is much more sore than when I get a flu shot. Slept great and feel great.
The second shot is what it is. It will be like the last 10k of a 40k time trial. I will suffer through it like everyone else. I will be glad when it is over and I will be glad that I did it.