Suggest Remedyfor Swollen Knee

48 yr old female, 5'4", 189lbs bp under control take atacand. My right knee has been feeling swollen and often heavy for several months now. I just joined Curves on Friday and worked out on Friday and Saturday. The step machine gave me a lot of pain on the right knee. I was only on it for 30 seconds the first day and 2 x 30 seconds the 2nd day. Today, my knee has given out on me 3x while going down the stairs and is swollen on the outside of it. Stills feels heavy but no pain. ????