Hi Beth! For me, the biggest problem with sitting (along with standing, walking, etc.) is if my arm hangs without any support. When I am sitting I try to make sure I have a chair with arm rests, and/or a pillow in my lap. Laying flat for me is really difficult...in fact, I use an adjustable bed, and never have it completely flat.

Another thing about sitting for me is if I have pressure against my shoulder blade, like sitting in a hard-backed chair...that hurts, too; sometimes even the pressure from a soft chair against my shoulder blade is really uncomfortable.

When I'm in a lot of pain, I find lying down on my "good" side with pillows under my arm and my head raised a little is most comfortable, just to take the pulling pressure off my collarbone.

Take care...
Donna