Why does my knee feel stiff and heavy?

Hi doctor,

I am a 42-year-old woman who is a non-smoker and fit person, but I experience pain in my legs and feet. It started with a swollen and stiff knee, and then the pain moved to the other knee, then it goes to my feet. I cannot walk or do sit-ups without feeling constant pain. It goes away, and then it comes back. The swollen knee is warmer than the other when in pain. I have tested negative for rheumatoid factor. I have x-rays and MRIs, but no one can give me a straight answer about what to do. I started walking on the treadmill, which helps with the pain in the legs, but now the pain has moved to my arms. I guess it is some sort of inflammatory process, but I do not know what to do, and because of COVID-19, I cannot go to a specialist.

Hello doctor,

Three years ago, my legs started hurting, and the pain was either in one of the legs. I could not understand what caused it and what made it go away. Sometimes at night, I woke up from very severe pain. Two years ago, my knees started to swell, and I could not bend them. Then I started going to a different doctor (endocrinologist, rheumatologist, orthopedist), and they did different tests. But no one could tell me what was wrong. One day my right knee got so swollen that I went to an orthopedist, and he made an infusion of blood into the knee. Another doctor wanted me to hospitalize so they can do more tests, but the pandemic started, and I could not do it. I started moving more, which helps my legs not to hurt as much. But that does not make the pain go away. My left arm started hurting the same way, and it is hard for me to move it (mainly in the shoulder area). I also have strong headaches sometimes, and they do not pass for days. I do not know if that is related to the pain in my limbs. I have not had any other diseases. For the last 10 to 12 years, I have not even gotten the flu, a cold, or anything like that. I am not taking any kind of medicine.