Yup, you're over thinking it -- pretty common among the newly diagnosed, so don't sweat it.
I suggest that you quit testing the area (quit stretching to see if it still hurts) for a few days, drink plenty of water, and if it's still there in 4-5 days call your Dr and ask about
It may be that you need more than plaquenil.
Lynnwood, Lupus & Sjogren's Moderator, Dx: 2002DIAGNOSING LUPUS & HW's LUPUS 101
"Life is far too important to be taken seriously." - Oscar Wilde