Player movement not working

I have this script to move the player (and their gun) and I can't figure out why it's not working. The debug.log("blah") things show me that the if statements are activating but the player doesn't move at all. Here is the script:

 using UnityEngine;

 public class PlayerController : MonoBehaviour {

     public GameObject pBody;
     public GameObject pGunOrigin;
     public static float speed;
     Vector3 gOffset;
     private bool right;
     private bool left;
     private bool forward;
     private bool backward;
     public Rigidbody rbody;
     void Start () {
         gOffset = pGunOrigin.transform.position - transform.position;
         rbody = GetComponent<Rigidbody>();
     }
     void FixedUpdate () {
         right = Input.GetKey(KeyCode.RightArrow);
         left = Input.GetKey(KeyCode.LeftArrow);
         forward = Input.GetKey(KeyCode.UpArrow);
         backward = Input.GetKey(KeyCode.DownArrow);
         if (right == true && left == false)
         {
             Debug.Log("Right");
             rbody.AddForce(new Vector3(speed, 0, 0), ForceMode.VelocityChange);
         }
         if (left == true && right == false)
         {
             Debug.Log("Left");
             rbody.AddForce(new Vector3(-speed, 0, 0), ForceMode.VelocityChange);
         }
         if (forward == true && backward == false)
         {
             Debug.Log("Forward");
             rbody.AddForce(new Vector3(0, 0, speed), ForceMode.VelocityChange);
         }
         if (backward == true && forward == false)
         {
             Debug.Log("Backward");
             rbody.AddForce(new Vector3(0, 0, -speed), ForceMode.VelocityChange);
         }
         pGunOrigin.transform.position = pBody.transform.position + gOffset;
     }
 }