Health & Medical >> Do I have Plantar Fasciitis?

I was on vacation last week and I climbed the Great Wall of China (was the most awesome experience!). I have had chronic pain in my left knee from an old kickboxing injury, which started to cause discomfort when I was coming back down the Great Wall. Therefore, I was trying not to use that leg as much as possible. So I was practically hopping down on my right leg, therefore putting a lot of pressure on it. I think I injured my right knee and foot in doing so. So 2 days ago, which is a week after the Great Wall climb, I thought I had recovered and went on a hike with my dog. While coming downhill again, I felt pain in my right knee and foot. When I got home, the pain in my right knee slowly disappeared, but the inside arch of my foot is still in pain. Today it is still painful to walk. I looked up the condition, and may have developed Plantar Fasciitis? If I do, what kind of stretches or excercise should I do to treat it? And what kind of excercises/activities do I have to avoid? Thanks in advance, Ed