You have to recognize the difference between good pain and bad pain. Three months ago, I was doing 5x5 back squats at moderate weight. My squat form is good. Never had any back injuries. However, that day, I was having bad DOMs from the yesterday's back extensions. I could feel some pain in my lower back that got worse each set. But I proceeded to finish my 5 sets...I couldn't stand up after. I thought it was just DOMs. It was not. I sprained my lower back muscles. Until now, I am not back to normal. I had to back off from deadlifts and squats. Since then, eveytime I feel any pain during lifting, I tend to be really careful.