What Causes Knee Pain After An ACL Surgery?

Hello, I had acl surgery on my left knee a little over a year ago. It has healed very well. Although, my right knee is hurting now. I am assuming that it is because of the over use I put it through. I am at the decision on whether I should get a lighter brace for my leg that had surgery or not. (I play sports, so I used a heavy duty brace for the year.) But, I was also wondering whether or not I should try to get something for my right leg. My surgeon says that I should be fine because the brace protects my right leg as well as the leg that had surgery. But my right leg is having pain. When I get it checked out, they say that everything is normal. I would just feel comfortable with something on my right leg, even if it is small. So I am wondering if that is a good idea. Or if I should just go with a smaller brace for the leg that had surgery. -RP