hello mr ismail
from the above complaints you have mentioned above i have inferred that you feel that one testis is bigger than the other.
mr ismail it could be normal or there may be some problem but nothing can be told with out completely examining your son.
i would advise you to consult a general surgeon
or a pediatric surgeon and get a complete test done.
a scrotal ultrasound
can be done to diagnose the problem.
i wish your son good health and i hope i have helped you.