Back squats

After feeling back pain on 9/7 with the kettlebell swings, which had followed 190-lb back squats, I went to see Dave for a training session to see if he could spot the problem. He and Scott looked at me squatting and found that indeed I’m not fully stabilizing my mid-back, and that I’m not engaging my hip flexors to pull down. Instead I’m using my stronger legs (than my back) to fight gravity and then finish the lift. I need to practice perfectly stabilized, lighter back squats and have somebody watch me. But will I? I’m almost always working out alone.