How to move a camera combination of x and y axis

using UnityEngine; using System.Collections;

public class CameraShake : MonoBehaviour {

 public ShakeTrigger shaketrigger;
 private float startingShakeDistance = 8;
 private float decreasePercentage = 5;
 private float shakeSpeed = 50;
 private int numberOfShakes = 10;
 private Camera cam;

 public IEnumerator CameraShakes () {
     float hitTime = Time.time;
     float originalPosition = cam.transform.localPosition.x;
     int shake = 0;
     float shakeDistance = startingShakeDistance;

     for(shake = numberOfShakes; shake >= numberOfShakes; shake--)
     {
         float timer = (Time.time - hitTime)*shakeSpeed;
         cam.transform.localPosition.x = originalPosition + Mathf.Sin(timer) * shakeDistance;

         if(timer > Mathf.PI*2)
         {
             hitTime = Time.time;
             shakeDistance *= decreasePercentage;
             shake --;
         }
         yield return null;
     }
     cam.transform.localPosition.x = originalPosition;
 }
 

}

using UnityEngine; using System.Collections;

public class ShakeTrigger : MonoBehaviour {

 public CameraShake m_camerashake;
 
 void Start () {
     
     m_camerashake = GameObject.Find("CameraFPS").GetComponents(CameraShake);
     
 }
 
 void OnTriggerEnter(Collider Col)
 {
     if(Col.tag == "Player")
     {
         StartCoroutine(m_camerashake.CameraShakes());
     }
 }

}

Assets/Scripts/EQ/CameraShake.cs(33,31): error CS1612: Cannot modify a value type return value of `UnityEngine.Transform.localPosition'. Consider storing the value in a temporary variable

please help me dont know how to resovle this problem i want to shake my camera like there is an Eq but it says i cant store localPosition x to a original positon