Problems with Spring Joint 2D

Greetings. I'm making a 2D pinball type game in Unity3d. I used the Spring Joint 2D function for the trigger of the ball but it is unstable. When do the pulling motion with the mouse or the keyboard the object is oscillating. He does not make a smooth movement. Is going up and down several times. Below the script to control with the mouse:

 #pragma strict
 
 var click : boolean = false;
 var PosAnt : Vector3;
 
 function Start () 
 {
 
 }
 
 function Update () 
 {
     if (Input.GetMouseButtonUp(0))
     {
         click = false;
     }
 
     if (click == true)
     {
 //          guiTexture.pixelInset.x += Input.mousePosition.x - PosAnt.x;
           transform.position.y += Input.mousePosition.y - PosAnt.y;
           PosAnt = Input.mousePosition;
     }
 }
 
 function OnMouseOver(){
  
      if (Input.GetMouseButton(0))
      {
           click = true;
           PosAnt = Input.mousePosition;
      }
 }

How can I solve this problem? Thank you for your attention.