I went to the gym today and did deadlifts despite a sore back. My back wasn't aching from deadlifting, but instead from poor form on overhead barbell presses I did on Sunday. For some reason, I was arching my back rather than just keeping it straight. I wasn't pressing near-maximum weights either. I was doing around 65% of my single-rep max. It was just bad form, and by the time I figured it out midway through the second set, the damage was done.
The deadlifts went well. I did 6 sets of 3 reps each, not pushing things too hard. Lat pulldowns hurt and I had to quit those, and pullups were painful too. I hit the heavy bag for 15 minutes, working up a nice sweat, and called it a day.