Ever since I've gotten up my lower ab muscles have been sore like they've been over worked or something. The thing is, I haven't been exerting myself recently. My lower back is very stiff as well. If it doesn't get better I'll have to see my doctor.
Did you have some sort of jarring injury in the past few days? Did you slip and catch yourself or fall? Just some ideas. Those things could make your abdomen and back stiff or hurt. I hope you feel better soon!