I Have Knee Pain That Started A Week Or So

I have knee pain that started a week or so before Christmas. It started behind the knee and now it's on the knee and sometimes the pain travels down to mid shin. I've seen the Dr twice for this and he tells me it's tendinitis. I was walking each morning but now I can't because of the pain. He said to put ice on my knee which I have but it doesn't seem to help. What should I do next?