So you want to start exercising, but your joints are sore. Don't let painful joints get you down. Granted, you'll have some limitations, but just because you can't do it all doesn't necessarily mean you can't do anything.
Sometimes joints are sore because you lack strength in your joints and muscles. You might try a stationary bike to build strength in your joints and begin dropping pounds while you're at it. You can start small and gradually build up. Give it a month and you may find that your once painful joints are feeling better and that the strength in your joints is increasing.
"For you to see any results, you pretty much have to commit to this 3 times a week. More is better but 3 times a week to start is fine. Again, if you are new to this start with 15 minute sessions and work your way up to 25-30 minute sessions. It will be tough at the beginning but within a month you will notice a positive change. Your joints won’t be as sore, you will be stronger and you will be dropping pounds. And isn’t that what you want."
http://www.fitnessover50.org/want-to-lose-weight-but-have-sore-joints