What Causes Pain In Knees After Working Out?

Over the past 7 yrs I've been using an exercise bike 3 times a week for minutes. I consider my training intense. I actually started running, but injured my right knee and limped for a couple of weeks, so opted for a bike since it's less tress on the knees.Over the years I've felt some knee pain mostly in my right knee. Whenever I workout I also feel some pain. In the last two months I've been experiencing pain in both knees. Pain in the middle of the knee cap and below. Between the cap and lower leg bone. Last time I worked out was Tuesday night. Since yesterday my left knee has been popping slightly and seems weak. The right one is even worse. There was popping while I worked out. It's weak and there's slight pain on the side. While the pain has subsided the popping in the left continues and still weak. The right has some pain in some places. There's no redness or swelling. I would like to know the type of injury I sustained,will rest restore the the knee to normal, should I see a doctor, can over the counter medication help.