hi doctor, last wednesday i woke up with some knee pain and by the time i slept at night, it became unbearable. on thursday mornin my knee hurted a lot and got swollen.so i went to hospital and there they injected out yellow colored fluid from my knee. now there is a little relief from the pain and swelling but i am still not able to walk properley. doctors say that it is still not diagnosed. i want to know what it is n why is it happenin to me?? About me, i am 22 year old, female, with normal weight and active lifestyle.