Original post: https://www.reddit.com/r/posturepals/comments/1bsffn1/chronic_neck_pain_is_it_my_posture_or_screen/
"My prior PT said my posture was "textbook" with my standing desk, but I still don't feel great with it."
I dare to say that your PT has no idea what correctly functioning mechanism (good posture) looks like. I'm yet to meet a PT who knows this stuff. I don't think they teach them that at PT schools.
"except for my in low back.... a separate issue :)"
That is absolutely not a separate issue. It's just a different part of a body where symptoms show up. Your lowerback and your neck pain are different parts of a bigger problem.
Let me explain.
I have outlined your torso on the first image on the left. Then, I copy pasted it 3 times to the other images. (flipping / mirroring the drawing to suit the correct side).
You can see a pattern. It's a pattern of movement of the different parts of your body. For our purposes, we divide your torso into 3 parts. Top torso (ribcage), Mid torso (spine and abdominal cavity) and Lower torso (pelvis). As the arrows suggest, you tend to move the top and the bottom of the torso backwards, and you tend to push the middle torso forwards. It's consistent and it's apparently present regardless the activity you do.
If you would pay attention, you will find that it's there even when you lie down. It's there when you walk, it's there when you exercise. It's your habitual movements.
I can guarantee you that all your aches and pains are posture related.
That arch in your lowerback is what we call "shortening of your torso" and until you "expand the torso", you will have these issues.
It's all perfectly fixable, It just takes some learning and effort. If you have more questions, feel free to reach out.
PS: Get rid of the office chair with the coasters and replace it with something like this: https://www.ikea.com/au/en/p/bekvaem-step-stool-aspen-50225592/ (but preferably not from Ikea). Plus you will need to learn to sit on it too.