2D Object Following Finger

hi. i have this code to controll my game object by finger in mobile phone. but it works only on objects that they have 3D Collider . my game is 2D and objects have 2DCollider . what should i do to fix it?

     //flag to check if the user has tapped / clicked.
     //Set to true on click. Reset to false on reaching destination
     private bool flag = false;
     //destination point
     private Vector2 endPoint;
     //alter this to change the speed of the movement of player / gameobject
     public float duration = 0f;
     //vertical position of the gameobject
     private float xAxis;
 
 
     void Start()
     {
         //save the y axis value of gameobject
         xAxis = gameObject.transform.position.z;
     }
 
     // Update is called once per frame
     void Update()
     {
         
         //check if the screen is touched / clicked
         if ( (Input.GetMouseButton(0)))
         {
             //declare a variable of RaycastHit struct
             RaycastHit hit;
             //Create a Ray on the tapped / clicked position
             Ray ray;
             //for unity editor
             #if UNITY_EDITOR
             ray = Camera.main.ScreenPointToRay(Input.mousePosition);
             //for touch device
             #elif (UNITY_ANDROID || UNITY_IPHONE || UNITY_WP8)
             ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);
             #endif
 
             //Check if the ray hits any collider
             if (Physics.Raycast(ray, out hit))
             {
                 //set a flag to indicate to move the gameobject
                 flag = true;
                 //save the click / tap position
                 endPoint = hit.point;
                 //as we do not want to change the y axis value based on touch position, reset it to original y axis value
                 endPoint.x = xAxis;
                 //Debug.Log(endPoint);
             }
 
         }
         //check if the flag for movement is true and the current gameobject position is not same as the clicked / tapped position
         if (flag && !Mathf.Approximately(gameObject.transform.position.magnitude, endPoint.magnitude))
         { //&& !(V3Equal(transform.position, endPoint))){
             //move the gameobject to the desired position
             gameObject.transform.position = Vector3.Lerp(gameObject.transform.position, endPoint, 1 / (duration * (Vector3.Distance(gameObject.transform.position, endPoint))));
         }
         //set the movement indicator flag to false if the endPoint and current gameobject position are equal
         /*else if (flag && Mathf.Approximately(gameObject.transform.position.magnitude, endPoint.magnitude))
         {
             flag = false;
             Debug.Log("I am here");
         }*/
 
     }