Hi Herk. I would rest for at least one week then try running again. If your knee pain comes on then you should stop and ice it immediately for 20 mins. For now you can try wall squats 3-4 sets of 30-90 secs hold 3 times a day, bending up to 90 degrees at knee joint (prefer longer than 90 secs hold). I prefer you perform "isometric" type of strengthening while you resting. "Isometric" type of exercises are strengthening exercises without moving your joints. Please google it. Hope you get better soon Herk!