Easy 3 Miler: Knee Discomfort Still There

I have been resting my knee since last Saturday. This morning I got up and went for an easy 3 mile run in my neighborhood. I went slower than usual pace, and paid attention to my foot strikes, checking for any imbalances. I didn't notice any. Unfortunately, discomfort in my right knee surfaced around mile 2. Outer right edge of knee cap. It is not an excruciating pain, more like a nuisance. Frustrating!