I have made several wall hangings and found that dense quilting does cause the problem you are experiencing.
I now do what I call, my anchor quilting around the sections before I do more dense quilting within the "anchored" blocks, squares, rectangles in the quilt. When you outline these sections ( I do start from the center out), then I can go back and quilt "as desired" as they say, within each framed section.This framing of the sections keeps the fabric from drawing up so much when I do the additional quilting. Afraid I'm not very good at explaining....