ANOTHER Squatting Injury

So apparenlty I just don’t know how to squat, because this is the second time in the last 6 months that I’ve obtained a back injury from squatting while remaining injury-free on all my other lifts(touch wood).

On monday I adjusted some of my 5/3/1 squat numbers 'cos I realised my lower two work sets(which this week were at 70% and 80% of my 1RM) because somewhere down the line I made a mistake and my two ‘lower’ work sets were being done at a weight that was just detracting from my ‘all out’ set.

So I warmed up and got stuck in. The 70% set went ok. The 80% set went ok. But on the fourth rep of my 90% set, I get this strange shooting pain up my lower back and I immediately racked the weight. FWIW, I’m not 100% certain of this, but I think my back rounded on this weight and that resulted in the injury)

I’ve actually had this pain from squatting before so I didn’t worry. I foam rolled it a bit(I did my entire posterior chain actually) and even continued and finished off my workout stronger than I had hoped at the beginning of the day.

It was still a bit sore later so I decided that a bit of rest would be the best option and I did nothing strenuous for the night. Went to the cinema but nothing to exactly strain or stress it.

Next morning was pretty bad. It didn’t want to move and quite painful but I still got through the day and even a night shift at my job(semi-labour at night). I did that again today.

It’s only sore when I’m doing nothing for a long period of time. IE it wasn’t sore finishing off my training session at the gym. It’s not sore at work either. But if I’m sitting or lying down for long periods of time it become stiff and fairly painful.
Also, while sitting down, my neck seems to affect the area greatly. Cocking my neck to either side seems to produce pain in my lower back(again, only if I’m inactive)

I have almost no knowledge of the complexities of the back musculature andd I can only hazard a guess in saying that when my hamstrings or traps are ‘cold’ that they are exerting a greater pull on my pelvis or spine than my spinal erectors can handle at the moment.

Any suggestions on how to treat this is very welcome. I have no concern about it being a serious injury but I would really like to speed up the healing process.
Foam rolling has no effect on it(nor does it produce any sort of pain) and I have applied Deep Heat to it(I can’t remember the name of the american equivalent, I think it’s Icy/Hot) but I’m fairly sure that has only aggravated it.

Any help offered is appreciated guys.

I’ve had a similar experience when doing way too much volume and my back couldn’t take it anymore. For me it was a week before I could carry any kind of load without it being very uncomfortable. What I found that helped throughout the day was getting up and walking around the house/office at least once an hour to keep things from tightening up too much. I also wasn’t able to get much use out of the foam roller but two things were able to help. I made a deep tissue roller from two tennis balls taped together that was pretty good about hitting the low back muscles. I also found that most of my back pain was actually caused by one of my hips being so tight it was pulling my pelvis and straining the back. I used a lacrosse ball on the glute and piriformis for about 15 minutes and this alleviated 80% of the back pain. I was amazed.

Hope this helps.