Question
For about a month now my left knee has been in Chronic pain.  I am 6'3, 250 pounds.  I have never had an issue with my knees or pain in them before.  Recently I bought a King size mattress.  It is a Sealy pillowtop and is extremely soft.  There is about 5 inches of soft pillow mattress that you just sink in to.  I am wondering if the softness of my bed is resulting in knee pain?  I also have a desk job where I sit all day.  I am fairly active and have never had any mobiliazation problems before.

Answer
Your knee pain may be related to your back.  If you are in primarily a desk job, there are a pair of muscles (Psoas and Iliacus) that weaken from extended sitting.  When you straighten up and stretch these muscles, they can go into spasm, pulling on the low back.  If they are pulling just right, you can have pinching on the nerves that go down the leg to the knees, leading to your pain.  I would suggest a good chiropractor asses you and treat it, as well as address the Psoas/Iliacus issues.