I am doing A2G squats.. nothing too heavy. I am 5'10, 63kg and doing 125lb a2g squat..

But I notice after doing my warmup sets and getting on to it (have noticed it other days as well) the very bottom of my back right where it starts to go to my bum, only on the right side, hurts. Still hurting today and I went to the gym yesterday morning. When I have had this before, it didn't hurt the next day.

As far as I know I am doing everything ok - I am wondering if anyone would know what the most likely cause of this area of pain would be..?

Thanks guys.