Starting to increase training and find that occasionally - even after warming up - on starting to to jog I get a sharp stabbing pain on the upper front part of my right knee or just above. The knee occasionally aches afterwards and strangely at nighttime in bed. This is the same leg that was determined to overpronate more and be flat footed so I am now wearing orthotics. It doesn't happen everytime but certainly grabs my attention when it does. Also if I squat it a pain occasionally snatches across the upper front part of the knee. Could this be a plica problem??