I hear your frustration. In my experience, lower back pain, very near the top of glutes, some time after squats may have a lot to do with excessively tight hamstrings and hips (which will certainly alter lifting form in a negative way). I come from a history of years of distance running and also sitting all day at work with no mobility work... ever. I was very tight when I first started squatting and I found early on that the day after squatting I would have the tightest lower back, it was particularly noticeable when getting up from my desk, a general stiffness that would soon dissipate once I got moving around.
Can you get into an asian squat position, heels on the floor and stay there for a while without falling backwards?
For me the solution was to incorporate regular mobility work and foam rolling. I had to work hard not to try and rush through my sessions (previously I always hated 'stretching') and now I still focus on relaxing through my routine. I spend no more than 15 minutes a day maybe 4 or 5 days a week. For me it took a solid month for the issue to resolve. It does take a bit of discipline to make sure your working your mobility, but it is important and should be a part of what your doing whether you're lifting or not. Also improving your mobility will almost certainly help with maintaining form through out any lift.
With regards to form, I would suggest really focussing on what your body is doing durning any lift, you're in the best place to know if what your doing is putting you in a compromising position, it can be hard sometimes to rein it in when you really want to go for it, but injuries are more annoying than not putting more weight on the bar. Squats are never comfortable if you're working it hard, but you should feel neutral and solid in your core throughout the lift and know where everything else is and/or should be - feet, knees, hips, shoulders, chin, etc. I would echo what's been previously said and deload until you feel comfortable both during and after your sessions and then work back up in a slow, controlled and methodical way.
Someone also mentioned epsom salt baths, I've also personally found a magnesium supplement to be really helpful with general stiffness/soreness after training.
Just stick with air squats.
People who load up with weights love to say how great it is....until they destroy their backs.
Care to cite any actual evidence of this?
Originally Posted by OnlyBodyWeight
Won't destroy your back if its in the correct position. You will strengthen your back immensely. Air squats are a waste of time if you are trying to build muscle and strength.