I had hydrocele in my right testicles and it was gone . but in the few days past i had some pain in it and in the cord. i notice that it came back?

See your doctor: Go back and talk to your doctor. Hydroceles are caused by fluid accumulation in the scrotum. Yes it may go away on its own and yes it may be drained but there's also a chance either way for it to accumulate again. If there is pain or discomfort ask your doctor about more permanent solution. Also ask about possible hernia leading to hydrocele

Hydrocele: can recur. So if you feel that "its back", you need to see the surgeon who did the surgery for evaluation. It could be something else, so an evaluation is essential at this point.