Original post: https://www.reddit.com/r/posturepals/comments/1724pqi/upper_and_lower_back_pain_please_help/
100% posture related problems.
Just very quickly, what is going on (gotta sort out the kids for school in a minute):
The blue and white markers, in order are: Front of ankles, knees, iliacs (anterior superior iliac spine) bottom and top sternum. All these points should be on the green line.
You are rotating your pelvis (APT), which means that you are shifting the iliacs too far forward and down, and lifting your sacrum too high up (that's the green dot). Rotation of your pelvis indicated by white arrow.
You are also severely rotating your ribcage, except in the exact opposite direction to the pelvis. You can see it by the sternum being inclined backwards at the top, in relation to the bottom sternum. Again, this rotation indicated by the other white arrow.
So, now, you have 2 major parts of your torso rotating, in opposite directions. The effect on the middle torso (your spine and abdominal cavity) is this severe arch in your lowerback (red curve), pushing the abdomen forwards. That part of your body (the lowerback) should be flat!. And so should be your belly.
You are also heavily retracting your arms backwards (again, in relation to your torso).
And the same retraction is happening with your head.
See the brown line I lined up there? Let's call it the "broomstick test". You place a broomstick (or any straight edge) on your sacrum and between your shoulderblades.
If there is a space between your L3 (the apex of your lowerback arch) and the stick, which there is a lot of space in your case, you know you are shortening your torso. As I said, your L3 would ideally be flat on the stick. Also, you can see the back of your head touching the stick. The head should be well and truly forwards from the stick.
Imagine you would "fill" in the cavity in the lowerback, at least that much space would have to be created between the stick and the back of the head.
To start fixing it, you need to study about how the human mechansim functions: you can start with following these free resources:
https://goodposture.studio/resources
But sooner or later, you will still need a teacher if you want to get reasonably fast results.
List of teachers I know of is here: https://goodposture.studio/iat-teachers