Discomfort in knee. Is slightly twisted.

7 years back i had a sports injury which resulted in a partial ligament tear. Post bed rest and physio sessions, I got better. Sometimes increased activity level(like walking too much or running or dancing) would cause pain or discomfort. Sometimes the knee would get unstable and jerk even at moderate or usual activity level causing pain or discomfort for a few days. However, i had been okay with the way things were. This year i started running and the pain/discomfort has become a constant feeling for the past few months. Since i was travelling recently, the activity level increased to much higher than usual. So has the pain. even while sitting on a chair it feels like the knee is slightly twisted.