Old timers used to do things called deep knee bends. We call em squats. Do a bunch, lunges etc. The more blood you pump through your legs the sooner you'll feel better. This means you should get a training session in but maybe skip the PR's. Frankly, I've noticed that if I'm in pain but not injured I have super good sessions, and a lot of other people do as well. I suspect its an endorphin thing, so maybe you'll kill it tomorrow. But at the least get your self moving, inactivity never cured nothing.