I got my second dose of Moderna around noon one day and I started feeling rocky the next afternoon with a little bit of fever. I had kind of a rough night that night, but by the next morning I felt much better and by the afternoon I was back to normal. My wife got hers at the same time and had somewhat less of a reaction than I did.My daughter had a bit of a hangover the morning following, well over 18 hours after, but I didn't have any problems.
Acting on advice I got here, I did a few pushups right after getting the shot as well as when I got home. It seems to me that my arm wasn't as sore as it was after the first shot, but that's hard to quantify, especially as both shoulders were sore from doing the pushups. I need to get more exercise. ;^)