I have been focusing more on my tallstanding. After a day which involved a lot of standing, I felt rather sore on either side of my sacrum. It feels more like muscle soreness than stiffness or pain which I used to experience. I was wondering if this is common or indicative of something? I feel the soreness immediately after doing my mini squat. I found it kind of suprising since it is not my first effort in tipping my pelvis as I have had a lot of success with stack sitting and hip hinging.