Player not moving left or right

My player moves forward and backward, but not left and right. I am new to Unity, so any help will be appreciated`using UnityEngine;

public class PlayerMovement01 : MonoBehaviour {

// This is a reference to the Rigidbody component called "rb"
public Rigidbody rb;

public float forwardForce = 500f;
public float sidewaysForce = 500f;

void FixedUpdate ()
{
    if (Input.GetKey("w"))
    {
        rb.AddForce(0, 0, forwardForce * Time.deltaTime);
    }
    if (Input.GetKey("s"))
    {
        rb.AddForce(0, 0, -forwardForce * Time.deltaTime);
    }
    if ( Input.GetKey("d") )
    {
        rb.AddForce(sidewaysForce * Time.deltaTime, 0, 0);
    }
    if ( Input.GetKey("a") )
    {
        rb.AddForce(-sidewaysForce * Time.deltaTime, 0, 0);
    }
}

}

Nevermind, just fixed it! My X position on the object was freezed!