i dont know why the mainObject is moved when i click on game, for example, in the scene is in the position (0,0,0), and in game automaticly it goes to the position (0,0,-10)
pls help me 
This is impossible to debug with the information provided. Does it have a rigidbody? Gravity? Is it falling on something? What version of Unity? What scripts? What components? Is it a model? Where is its pivot point? Does it have child objects?
I can not replicate this problem in 5.5.
it has a RigidBody
5 of gravity scale
ye, its falling, but when i put it on the floor, i have the same problem
version 5.4
i have created a Script to make the camera follow my character
The gameObject has a rigidbody2D, transform, and an animator
the child of game object has a circle collider
It a 2D model made with sprites of a monkey
pivot point = its center
it has child object, a body, and body child onjects like leg or a tail