What Causes Pain And Bump On Lateral Side Of Knee During Movement?

A recent fall has caused pain in my knee when I flex past 90 to 100 degrees and when I have been on my feet for multiple hours. Visually you can see a bump on the lateral side by my knee cap. I am concerned because this is a knee that I had ACL surgery on 10 years ago. Does this require medical attention or should I continue to ice and rest it when I am not working? What could be possible injuries from fall?