2D - Object follow cursor on X-axis.

I've been searching around but can't seem to find the answer of my question. I'm very new to Unity so please take everything with a bit of salt and explain simple if you have a solution, thanks in advance!

Trying to show what i want to accomplish with this picture i've made above, I want the object to follow the cursor but still stay on the ground-surface. Most of the things i've found the Object moves to the cursor (The ball starts flying and gets the exactly same position as the cursor and ignores everything else). I just want it to "move with" the cursor in X-axis and not in Y-axis ==> Always stay on the platform.

 using UnityEngine;
 using System.Collections;
 
 public class FollowMouse : MonoBehaviour 
 {
     // Use this for initialization
     void Start ()
     {
 
     }
     
     // Update is called once per frame
     void Update ()
     {
         float dist = transform.position.z - Camera.main.transform.position.z;
         Vector3 pos = Input.mousePosition;
         pos.z = dist;
         pos = Camera.main.ScreenToWorldPoint(pos);
         pos.y = transform.position.y;
         transform.position = pos;
     }
 }

UPDATE : Seems like i kinda fixed it myself, It's not that smooth thought, it's moving SUPER fast wich i don't want and colliding pretty weird (I have it constantly bouncing)