Here's a great article on breathing that can then lead you to some other resources on breathing, as well as on movement. As a society we now sit more than we do anything else. More than sleeping, moving, rolling, playing. You know this isn't healthy right?? You know that getting back down on the ground and moving around down there will serve your body well. So, get down and do it. Practice crawling again, do those knees hurt? Ouch, I know mine don't like crawling at all. I never actually crawled, so when I had a child and she was following along in my footsteps (:-) and being a bum scooter, I lovingly touched her foot and encouraged a roll of that foot and fed her body over onto all fours and she was off and away crawling. Yeah for it being easy with her, and for the fact that she could develop that crawling activity that can hopefully serve her well years down the road!
also for other great squatting support. Ido Portal can inspire you here: