maybe a bit less HIIT and a bit more yoga in your life could help?!
that lower back pain thing is horrible... and you'll want to take care of that before it gets worse over time... the "3rd world squat", I dodn't know if there's a more politically correct term for it... but that's what helped me with compression related problems in the lower spine... do that for a few minutes every day, if you're able to even reach that position, to give the tendons a good stretch!
I’m actually quite flexible. I can do the Asian squat very comfortably. I have been doing flexibility exercises since my early twenties because of this problem that happens with my lower back every once in a while. It usually hits me when I’m overtired or under a lot of stress. One thing that I do whenever it happens is to lie down on a tennis ball and move around to massage my muscles. It helps quite a bit.
hahaha... I have a tennis ball in my desk's drawer, too. I usually use it standing against the wall, though. My frequently problematic area is more in the upper back.
that sounds even worse... lol
I'm not very big on political correctness as you might've already guessed. :-D