child object transform.position not working properly

So I have a child gameobject assigned to Player (also a gameobject). The child is a 3D Text that i have assigned to a variable called popuptext. I am trying to edit its position to make it move upward slowly on collision with a popup in the game. The problem is that it doesn't seem to be moving upwards as intended. Here is my code :

 IEnumerator PopUpTexter() {
         popuptext.SetActive(true);
         step = speed * Time.deltaTime;
         Debug.Log (step);
         var initPosition = popuptext.transform.position;
         var currentPosition = initPosition;
         var targetPosition = initPosition;
         targetPosition.y += 30;
         while(currentPosition != targetPosition)
         {
             popuptext.transform.position = Vector3.MoveTowards(popuptext.transform.position, targetPosition, step);
             currentPosition = popuptext.transform.position;
             Debug.Log (currentPosition);
         }
 
         popuptext.transform.position = initPosition;
         yield return new WaitForSeconds(1);
         popuptext.SetActive(false);
 
     }

any help would be appreciated.