Today was front squat day (with heels on plates). Warmed-up, dynamic stretching, BW squats. Then, first rep of the first set with 95, I immediately felt some pain in the lower back, L5 or so, when at parallel. Of course being stubborn I still finished my sets but felt pretty weak and had back pain.
Just for fun I tried a back squat and I felt no pain or discomfort at all…deadlifts are fine too.
I benched yesterday and arched/contracted my back too much and felt some pain after the last heavy set for a couple minutes. I wonder if that could be related?