i have this problem since few years now. Iam 28 years old female. And have alot of trouble with my knees especially in winters. They are absolutly fine wen i walk or go to gym. The problem starts wen i am sitting or sleeping. the pain starts building up if i am sitting within 5 minutes. to release the pain i need to stretch my leg. then the knee wud crack with alot of pain. i went to GP. he did a xray which i cudnt understand as its not a fracture and as per my expectation no results came in and GP advised that nothing is wrong with it. May be i should move my joints more. With high disappointment from GP my pain still conitinues every year it seems to grow and i feel its getting worst with the time. EVerytime i stretch while i sleep i can feel the pain so much sometimes i wake up with almost a scream. i hope anybody can help on this before i start goin to a specialist and spend alot of money