An injury, a medical condition, or bad posture can all cause knee pain. Rest, ice, compression, and elevation may manage... moreAn injury, a medical condition, or bad posture can all cause knee pain. Rest, ice, compression, and elevation may manage minor knee pain. But if this treatment isn't helping after a week, you should see a Knee Pain doctor at Long Island, who is highly skilled in the diagnosis and treatment of all sorts of knee conditions.