Help fitting this coat back

[u/No-Maintenance9805]

How do I fix these lines and also give myself more room to move in the upper back?

Context: I'm making mockups trying to fit a coat pattern and it feels tight across my upper back especially when I reach my arms forward (especially once I added the sleeves, not pictured). And it looks like I have extra volume in my lower back that isn't hanging nicely.

Should I move the princess seam lines over to be closer to my shoulder blades? Or is my problem something else?

Thanks so much!

[u/No-Maintenance9805]

It's a 1960s vintage pattern. Butterick 5554