I have arthritis in one knee. Recently I was fitted for some really great sneakers at a local shoestore. They help me walk more, and I do have less knee pain. But now (and I guess it was coming all the time anyway) the tendons in back of my ankles hurt. This pain is in both ankles, but actually more so in the leg without the arthritic knee. I felt the tendon (or whatever it is) the other day after walking more than 10,000 steps, and it had a round knot in it. The ankle of the bad knee leg had a knot, too, but not as big. Any ideas what this knot is, and how to get rid of this pain?