I m a 54 year old male,smoker, I have had very bad knee pain in both knees the last 2 days, some swelling in my left knee...pain is centered around the knees with sharp pain in back side of legs behind knees. This happened about 3 months ago in only my left knee, lasted a few days and went away. At the time I saw an rtho. he took x-rays but couldn t find anything ? Prior to this no issues with me knees....Plan on seeing my doctor tomorrow, but was wondering what you thought....thank you