While doing a 21 mile long run last week, I stepped into a pothole enough to make me fall down. Hopped back up and continued running. Later during the run, developed a slight pain on lower part of knee towards the inside of leg. It feels like it is near surface of skin and nothing deep. Have run on it every other day and it seems to get a little better each day rest. It does not hurt when I land and bear weight on that knee, rather I only feel it when the leg swings out or strides forward. I know nothing about knees or what I have.