What Causes Pain In The Knee On Bending?

I am getting pain in my right knee on kneeling down or when folding my legs , since the last 25-30 days.I have not hurt myself but do some cycling about three times a week for twenty minutes or so.I am fifty year old male and have a family history of gout but my last blood test about six months back showed uric acid levels about normal. Please advise.