If my knee hurts when i straighten my leg after bending my knees. is that normal if i have chondramalacia?

Depends: If you have been diagnosed with chondromalacia then you can certainly expect pain when straightening your knee after having it bent. That being said, the pain would usually be in the front of the knee at the knee cap rather than in the knee joint itself. Your condition affects the patellofemoral joint located in front of the knee joint proper.

Possibly: Possibly. Could also be patellar tracking. See orthopedic surgeon or rheumatologist.