My surgery was a dislocated knee. they say it's from playing sports. but i didn't really play sports because of my knee. pain in knee and swelling?

Evaluation: Knee dislocations and patella dislocations are two different things. I'd assume you are having a patellar dislocation. There are several reasons for this: congenital internal rotation of femur or tibia, trochlear dysplasia, medial patellar retinacular tear, increased q-angle, etc. I'd see an orthopedic surgeon to evaluate the reason you're having recurrent patellar dislocations.