Monday & Tuesday running

Two running workouts; Steven's Creek Trail on Monday for 30 mins, and a run around shoreline before work on tuesday. The tuesday workout didn't go so well; after about 25 mins I had pain in my left knee so I switched to walking. Its been twanging on and off for the rest of the day. Lots of different advice from people; I suspect I probably need to work on my technique, and not ramp up so quickly. I'll take a couple of days off and then try it again next week.