Swelling is a classic sign of inflammation. Rubbing it may reduce the pain, but the key to long term success is to identify the cause of the inflammation. If it gets inflamed from an activity, that is not normal and usually has a mechanical or structural cause. Hopefully you can find someone that can identify the source and provide you more than temporary relief.

There are several causes to a swollen knee: injury, fluid build-up, post-surgical edema. Massaging a swollen knee is not recommended. Icing a swollen knee is best. Attaining proper ROM exercises from a PT or Chiropractor would be the next step, once the swelling begins to subside.