Thanks for the advice, Anna.
Last night, I noticed that my traps felt almost normal for the first time since January or February. I've been "off" kettlebells for five or six weeks, and it's taken fully that long for the traps to heal. (I went to a doctor last week and he confirmed that it's almost certainly just muscle pain that I'm feeling).
I did three 50-lb military presses with each arm this morning, just to see how they felt. So far, so good.
I plan to carefully ease back into S&S, paying close attention to any ongoing soreness. Being a newbie to strength training, I didn't realize that I was developing chronic soreness in my upper back; I thought the soreness would just go away over time. I have a 25-lb kettlebell, and I might start really slowly--like one set of 5 swings at first, and a couple "naked" (or "shoe") get-ups. If that's too much, I might buy something lighter, like a 10-pounder.
I'm still waiting for my knee to feel better. Going on two months now....