Pain in right knee, body heat, swelling. Taken naproxen. Treatment?

For last two weeks I have terrible pain in my right knee .Actually now, the other one start hurting too,because I walk so bad and giving the entire body weight on my left knee. This happen when I was going to the pool. I see that problem with me before, wherever my body get very hot, like in this situation from the sun and I go to cold water I end up like this. I took one naproxen 250g, but I start swelling after . The pain was so much less but im very sensitive to so many medication . I don t know what to do, plus I m over weight what probobly cost more problem.