Well Hi there
Welcome to this wonderful board. You know when I read your question, I had to take a double take. You see, I was only reading about this very thing yesterday under "can anxiety cause arthritis"? There are alot on this post who feel that it can.
I alone in my family have rheumatoid arthritis, so I can say it is possible to be the only one
I am just wondering though, could your arthritis be a result of wear and tear on that joint?
This wear and tear is quite common and will be a result of use of that joint. Resting it will help.
Can you think of a reason why your knee is inflamed? Can your knee be stressed because of physical activity?
So I would say yes, a joint can be inflamed both by mental stress and physical stress.
The joints of the legs are most suseptable because they bear so much weight on them.