is this what getting old is like?

So here's an update for anyone who cares. The MRI I had done on my knee turned up absolutely nothing. So they wanted to do blood work. That turned up nothing as well. They tested for arthritis and other joint disorders. Nothing. The fluid was tested for infection and gout. Nothing there either. So I went to the doctor yesterday and he basically told me he doesn't know what's wrong with me. He said it isn't normal for inflammation like that, especially without injury. He said to just keep an eye on it and if it swells up again, I should see a rheumatologist. That's all fine and dandy except I still can't bend my leg completely. As in, I can't sit on my knees. Which kind of sucks when you have a one-year old and you're on the floor a lot. He said this should get better as well, but I have a feeling it won't. It's just all too weird.