That sucks, I hope things get better for you quickly.
I tried to squat the empty bar today and my left QL seized up very painfully. I've dealt with a certain degree of back pain in the past, but if I'm not able to squat the bar without my back attempting a murder suicide then something isn't right. Recovery is an issue, as I don't get enough sleep and I walk around on concrete all day, but I don't know if that's sufficient to explain this. I am not sure how I'm going to proceed. I need to do something to build myself back up and rehab this before I'm able to train properly, I'm just not sure what that is.
I feel the pain on both ends of my left QL, and there is some tightness in the outside of my left glute. I can move my legs independently pretty well, but any flexion of the spine or hips is limited due to tightness and pain.
That sucks, I hope things get better for you quickly.
Does the pain also radiate into your hip flexor and leg and is it just on one side always?