There are many causes of acute monoarthritis (affecting only 1 joint) in a young person. Many of these are transient, but given your symptoms it is impossible to know for sure. An evaluation by a physician is certainly warranted
Knee joint stiff and painful.
I am 34 yrs old. It started about 3 months ago. My right knee felt stiff and swelled up. It was tender and when pressed was painful. I had and continue to have difficulties, walking or driving. My right knee joint is always painful and stiff. I have not seen any doctor yet. Please advise.