So, when I do conventional style dead lifts, I try hard to keep my back straight, use my lower body/hips, and keep my shoulders pulled back/chest out. How come recently, when I dead lift, like the middle of my back, like where my spine is, in between my shoulder blades, it gets uncomfortable and kinda hurts. The pain is not that much, it just feels weird. This is weird, because before I used to never feel anything on my upper back, only my lower back when I would perform with improper technique. Anyone else experience this?