I have the same issue. Very sore knees after starting up some fairly strenous working out .
Recently one knee hurts in the back and sometimes catches when I walk causing intense pain. I want to get back to the exercising and Dont want surgery.
I am a veteran when it comes to knee problems. Torn meniscus cartilage, 2 knee scopes (arthroscopic surgeries), and finally a total knee replacement. If your knee is swelling, especially in the morning after sleeping, it may be a torn meniscus cartilage. The older we get, the more brittle our cartilage becomes and the more prone it is to damage from impact, etc... I have had lots of injuries over the years but the knee had the worst pain of all. If you hurt bad enough to limit your daily activities, you need to see your primary care physician and see about getting an MRI done. If you have torn your meniscus and get it diagnosed and treated in a timely manner, the surgery won't be too bad and the limitiations should be minimal as well as the heal up and rehab time. If you let it go and the little tear becomes a big one, like mine, you have brought much heartache upon yourself needlessly. If your knee is unstable it may be simply from the pain or it may be one the structural ligaments (ACL, PCL, MCL, etc...) and that can also be repaired via scope with minimal down time. Good luck and remember the old saying, "An ounce of prevention is worth a pound (ton) of cure."