1) Is it allowed to make little movements during namaz such as adjusting the clothes, itching on the face etc?

2) A person is praying namaz near a door. During namaz his son opens the door so that it interferes with ruku n sajda. Is it okay to close the door intentionally during namaz so as to complete sajda

1) Yes as long as they are not too excessive

2) Yes one can close the door while praying provided that he doesn’t turn away from the Qiblah, and he stays towards the Qiblah. So he can close the door and the prayer would be valid.