This is the thread for the 11 pm question. The one you feel silly asking, about the pain that moved, the spasm that changed how you're standing, the stiffness that's worse in the morning.
Most of what happens in a flare is alarming and ordinary at the same time. Ask here, and people who've been exactly where you are will answer, and so will I.
One rule that overrides everything else in this thread: numbness around your groin or the area you'd sit on, new bladder or bowel trouble, sciatica or numbness in both legs, a foot that drops or drags, leg weakness worsening by the day, or back pain with a fever. Don't post those here and wait. Go and get checked.