There can be lots of reasons for knee pain (foot problems, bad shoes, etc.) but, yes, diabetes 2 is associated with an increased risk of having joint pain and arthritis. You should get an examination in order to figure out whats going on.
You might want to check out the diabetes section and forum on the Health Central website and see what they have to say. Good luck that diabetes 2 and your knees.
http://www.healthcentral.com/diabetes/?ic=1102