Knees

So today, my knees are killing me. I don't know what is going on exactly. On the way down the steps this morning to get Lukin up, I thought my knees were being weird. They had this dull ache to them. They almost feel like they are separate entities today. I don't even get it. Then when I was walking into work, I tripped over my own feet and thought that it was because of my knees. If anyone has any advice for me and my knees, I would be glad to hear it.