I realized while meditating this evening that I tend to hold my shoulders up and forward. The guided progressive relaxation I use includes the instructions that the hands should lay "alongside the body, with the palms open toward the ceiling." This position has always felt uncomfortable to me; my natural inclination has been to lie with my palms down against the bed. This is the position that feels most "relaxed" for me. When I tried to do it as instructed, I felt my arms uncomfortably twisted in a way that became downright infuriating after 45 minutes of motionless contemplation.
Tonight, in something of a breakthrough, I realized why. Rolling my shoulders in tends to bias my arms toward the palms-down position. If I really relax and stretch the muscles in my chest and put my scapulae flat against the bed, it becomes quite natural and comfortable to lie with my palms open to the ceiling, to say nothing of how it improves my experience of my chest and upper back. I have a barrel chest which, at least as an adolescent, looked pretty strange with my spindly limbs and neck, and I imagine the habit of pulling my shoulders forward was an unconscious effort to minimize this. It's a habit that might also date to my bodybuilding days, as pulling the shoulders back tends to flatten and minimize the pecs whereas pulling them forward tends to bulge and emphasize the pecs, which, I am somewhat ashamed to admit, is something I once wanted to do.
I should think about ways to correct my habit, which I believe is both a lifting and a rounding of my shoulders. My father once told me (and now I wonder if he had an ulterior motive at the time) that he had corrected his own shoulder-rounding problem by having someone affix a piece of surgical tape across his upper back between his shoulder blades when they were in the proper position. Then if he started to pull them forward he would feel resistance and tightening in the tape and would be reminded to leave them back.
If I had somebody around here to apply the tape, I might just try that.