Pain in the upper hamstring, lower glute towards the lockout of squats

[poohguerrero]

The pain first occurred as discomfort during volume day squats (285 5x5) about four and a half months ago but got progressively worse with each set. Recovery day was pain free, so I assumed the previous session could have just been an off-day. On the third rep of ID (320 1x5) the pain flared up again, but I was able to complete the set (I probably should have racked it). The pain has gotten progressively worse to the point where I feel it at any weight above 135 and could not even complete my second warm up set today. It is now a sharp (deep) pain on the left leg where the hamstring and the glute meet and is accompanied by the bar speed slowing to a crawl towards the lockout (as seen in the video).

Video of last attempted warmup set: squat warmup pain - YouTube

I have tried:
resting it for two weeks (the pain came back by the second work set)
squatting less frequently
deloading all squats and deadlifts by 10%
isometric hip extensions before squatting
stretching the affected area

The pain does not follow me outside of the gym and, apart from squats, only comes up in the deadlift as a slight discomfort during the set up. I would appreciate any advice in fixing this as my strength has plummeted from not being able to squat properly.

[Mark Rippetoe]

You need a diagnosis/MRI.

[poohguerrero]

understood, thank you!

this might be obvious, but would you recommend stopping deadlifts and power cleans before having it diagnosed?

[Mark Rippetoe]

How long will a diagnosis take?