Congratulations on getting that first jab!! Probably tomorrow is when you'll notice some increased soreness and discomfort in that arm. At least this is the way it was for me with Moderna -- didn't notice much of anything until I arose from bed the following morning, and oh, yeah, got a kind of sore arm here.....that lasted a couple of days and then on the third day a little itching at the injection site, but that was that as far as the arm was concerned.
How was your 2nd shot?