Welcome at HCM.
Your details shows that most probably you are suffering from arthritis
knee.Although your x rays are looking get but the better way to check for this is to have MRI
investigation.You should do following to have relief in this-
-Start doing quadriceps exercises-
-Take a good analgesic
-Do warm fomentation over the knee.
-Keep your weight under control.
-There are some intra articular or in the joint injections which are helpful in early stages of arthritis.You may ask for them from your doctor.
Hope this all will help you.
With best wishes.