I’ll leave this for Joe or Bryce to give the more accurate reply, but it looks like you’re doing a front squat in this picture, and you don’t have the ankle mobility to reach proper depth and your back is leaning forward and compensating to get depth. I guess when you are squatting you’re using a lot of effort to keep the bar from rolling off? I’d suggest getting something for heel elevation to get proper depth through your ankles
I just do box squats now because of back pain, it always came back when I started squatting, I have butt wink also because I go too low for my active range of motion. Thats why box squats are decent variation for me(glute focused)
I’ve always been taught during a front squat your upper arms should remain parallel to the floor. Yours are angled down at a 45⁰ angle toward the floor. From the picture, it looks like you’re leaning forward to reach the depth, which is going to shift the weight forward over your toes, barbell looks to be tracking toward your toes in this picture rather than center of foot. You’re possibly putting your back into an awkward situation between supporting the load, and trying to keep your body from falling forward.