I'm finding (with age?) my knee joints are aggravated by long, slight pressure. In the bedroom we have a couch a couple feet away from the side of the bed. If I sit on that couch and rest my legs straight on the bed, my knees get sore from gravity. Or if I pull in a bit, let the knees bend out, they get sore from the lower legs being supported by the bed, but gravity on the thighs pulling down against the knee joint.
Aging, amirite?