I started having knee problems 10 years ago. I went to PT many times. I can't take non-steroidal meds so. I had to rely on Tylenol. I ended up with a knee replacement on the right knee in 08 and a replacement on the left knee last May.
In the meantime until you go that route, alternate heat/ice. Heat helps with the stiffness and ice relieves the pain. I don't think it can be stressed enough but exercise is very important. If you go to PT they will teach you exercises and you need to do them. Exercise of 3-4 days a week for 30 minutes, and stretching after, will keep your muscles loose and strong.