Dragging object in constrained area

I'm creating a game where the player starts a level by placing the golf ball in the placement box, so I draw a ray and if it hits a square with a tag "StartGreen", then it places the object at that place, but offset by the balls height so its on top.

That all works Fine and dandy. However, I want it so that the player can drag the ball around the box as long as they haven't lifted the mouse. to do this, I traced more rays while on Mouse Drag and if the ray hit within the box, then the ball position is updated.

My Problem: The object position is not updated while being dragged, is my understanding of how often onmouseDrag() incorrect, can i not call rays (should i not) in this function? if not could i go about this a better way? (maybe using bounds of the tee box?)

By the way: this.gameobject is the tee box which has this script attached, and onMouseUp works.

My Code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlaceGolfBall : MonoBehaviour {
 
     public Material onPadMat;
     public Material offPadMat;
     public GameObject itemInstance;
     bool goodHit = false;
     RaycastHit hit;
 
     float yPos;
    
 
     // Use this for initialization
     void Start () {
         gameObject.GetComponent<MeshRenderer>().material = offPadMat;
     }
     
     // Update is called once per frame
 
     //places the ball initially
     private void OnMouseDown()
     {
         if (!enabled) return;
 
         Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
         if (Physics.Raycast(ray, out hit)) {
             if (hit.transform.gameObject.tag == "StartGreen" && itemInstance != null)
             {
                 yPos = hit.point.y + itemInstance.GetComponent<MeshRenderer>().bounds.extents.y;
 
                 Vector3 position = new Vector3(hit.point.x, yPos, hit.point.z);
 
                 Instantiate(itemInstance, position, Quaternion.identity);
                
 
                 goodHit = true;
                 //gameObject.GetComponent<MeshRenderer>().material = onPadMat;
                 //debug.log("<color=green>placed successfully! script deactivated.</color>");
                 //this.enabled = false;
             }
             else {
                 Debug.Log("<color=red>Unsuccessful Placement</color>");
             }
         }
         
     }
 
     //if was placed, then can be dragged as long as the mouse is down.
     private void OnMouseDrag()
     {
         if (!enabled) return;
 
         if (goodHit) {
             print("wasGood");
             Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
             if (Physics.Raycast(ray, out hit)) {
                 if (hit.transform.gameObject.tag == "StartGreen") {
                     itemInstance.transform.position = new Vector3(hit.point.y, yPos, hit.point.z);
                 }
             }
         }
     }
 
     //deactivates the script now that the placement is over.
     private void OnMouseUp()
     {
         if (!enabled) return;
 
         gameObject.GetComponent<MeshRenderer>().material = onPadMat;
         Debug.Log("<color=green>placed successfully! script deactivated.</color>");
         this.enabled = false;
 
     }
 
 }