How to move an object relative to another moving object?

Hi, I am making a sign that moves up and down above a player's head while the player is in a zone that pops the sign over their head. My problem is that every time I try to get the sign to move in its local space, it keeps returning to the same position that I have specified in my Update() function - which is an offset from the player's current position. What should I change/use in my code to make this happen?

Ok, I finally got it figured out. It feels like there has to be some better way to do this with Unity, but this is the only working way I figured out to get a sign bouncing over the player's head as they moved around inside a zone.

This is the full source in case anyone else wants to figure out how to do something similar.

 using UnityEngine;
 using System.Collections;
 
 public class TriggerForest : MonoBehaviour {
 
     //private variables
     private bool playerInBounds;
     private bool bCreated; 
     private GameObject signObj;                             //displays the text
     private GameObject floatTextObj;                         //displays instructions to interact
     private static float initDuration = 0.8f;                 //controls duration that sign moves in a direction until switching
     private static float duration = initDuration;
     private static float speed = 0.5f;                         //controls speed that sign moves
     private Vector3 move = new Vector3(0.0f, 0.0f, 0.5f);     //controls direction that sign moves in
     private bool bDone = false;
 
     //public variables
     public GameObject player;
     public GameObject playerPosition;                         //always center on the player
     public GameObject forestSign;
     public GameObject floatText;
     public Vector3 signOffset = new Vector3(0.0f, 0.5f, 3.0f);         //set the default offset for displaying sign above player
     public Vector3 fTextOffset = new Vector3(0.0f, 0.5f, -1.5f);
 
     // Use this for initialization
     void Start () {
 
     }
 
     //check if player is insider trigger
     void OnTriggerEnter(Collider other) {
         if (other.gameObject.tag == "Player") {
             playerInBounds = true;
 
             //Debug.Log(playerInBounds); //test
             Debug.Log ("Entering forest.");
         }
     }
 
     void OnTriggerExit(Collider other) {
         if (other.gameObject.tag == "Player") {
             playerInBounds = false;
 
             //Destroy (other.gameObject); //test
             Debug.Log ("Leaving forest.");
         }
     }
 
     // Update is called once per frame
     void Update () {
 
         //alternative way to reference player
         //var player = GameObject.FindWithTag("Player");
 
         if (playerInBounds) {
 
             //check if user pressed the key to enter level (using e for now)
             //GetKeyDown occurs only once per press, compared to GetKey which continues to occur as long as button is pressed
             if(Input.GetKeyDown(KeyCode.E)) {
 
                 //reference documentation for the line below:    http://docs.unity3d.com/ScriptReference/Application.LoadLevel.html
 
                 //switch the scene to forest level
                 Application.LoadLevel("testSceneLoad");
             }
 
             //ensures we do not continue making objects; also init run once things for sign here
             if(!bCreated) {
 
                 //create objects from prefabs
                 signObj = (GameObject) Instantiate(forestSign, transform.position, transform.rotation);
                 floatTextObj = (GameObject) Instantiate(floatText, transform.position, transform.rotation);
 
                 //set the intial position of sign
                 signObj.transform.position = player.transform.position + signOffset;
 
                 //parent the sign to the player's position; this updates its position automatically
                 signObj.transform.parent = playerPosition.transform;
 
                 bCreated = true;
             }
 
             /* THE SIGN */
             //update position of sign
 
             //moves sign down
             if(!bDone) {
                 if(duration > 0.0f) {
                     
                     signObj.transform.Translate(move * speed * Time.deltaTime, Space.Self);
                     
                     duration -= Time.deltaTime;
                     if(duration <= 0.001f) {
                         duration = initDuration;
                         bDone = true;
                     }
                 }
             }
 
             //moves sign up
             if(bDone) {
                 if(duration > 0.0f) {
                     
                     signObj.transform.Translate(-move * speed * Time.deltaTime, Space.Self);
                     
                     duration -= Time.deltaTime;
                     if(duration <= 0.001f) {
                         duration = initDuration;
                         bDone = false;
                     }
                 }
             }
 
             //update rotation of sign
             var newRot = transform.rotation.eulerAngles;
             newRot.x = 0.0f; newRot.y = 180.0f; newRot.z = 0.0f;
             signObj.transform.rotation = Quaternion.Euler(newRot); //this sits the sign upright
 
 
             /* THE FLOATING TEXT */
             //update position of floating text
             floatTextObj.transform.position = player.transform.position + fTextOffset;
 
             //update rotation of floating text
             var newRot2 = transform.rotation.eulerAngles;
             newRot2.x = 90.0f; newRot2.y = 0.0f; newRot2.z = 0.0f;
             floatTextObj.transform.rotation = Quaternion.Euler(newRot2); //this sits the text upright
         }
         else {
             Destroy(signObj);
             Destroy (floatTextObj);
             bCreated = false;
         }
     }
 }