My knee feel some pain

Today, I went to the orthopedic hospital. Because of recently my knee feel some pain. I think that my legs didn't keep my body weight. But as time goes by my knee more and more pain. So I went to the hospital. Doctor said " Didn't you always exercise ? isn't it ?" But I'm always some exercise before go to bed. So I said "No. I every night have some exercise." " Then you must be perforce exercise. I think you'd better rest your legs. " And he prescription my leg. I must have physiotherapy. He injection to my leg. Very painful. Also shot my hips. After a long time I was shot. So a little scared. From now on I must take care my knee.