What is wrong with my knee? My knee hurts when I move it or put pressure on it, but it doesn't hurt to touch it. What is wrong? It hurts only time to time the pain is not constant.

A few thoughts. Osteoarthritis or degenerative wear down of your cartilage is a weight bearing problem and mostly hurts when you bear weight on it. Meniscus tears generally hurt when you put weight on it, squat, twist, turn, rise from a chair or do stairs. Get an evaluation from an orthopaedic surgeon and let them help you get better.
You. You may have a joint problem such as a cartilage or meniscal problem. The cartilage and meniscus line the joint but they are deep so it wouldn't hurt if you touch it. Sometimes this will heal on its own, if you don't aggravate it by heavy lifting or twisting. If it persists, please see an orthopedist for an evaluation. You will also have to be seen if you get increased pain, unusual symptoms like fever, or if your knee gives out on you.