knockback freezing game

Hello I have a IEnumerator script set up that knocks the player back when he collides with the enemy. I tried to set it up so the character would be knocked back in a different direction based on the position of the rigid bodies colliding, but whenever they collide it pauses the game, and when I hit the unpause button the character performs the correct knock back, so I'm wondering if it is a coding error on my part or maybe a setting I'm missing in the editor.

//variable from the collision handler class created in player

private BaddieCollision enemyCollider;

//variable being defined in the Start() method in player

enemyCollider = gameObject.GetComponent ();

IEnumerator function in player

 public IEnumerator Knockback(float knockDur, float knockbackPwr, Vector3 knockbackDir)
 {
     float timer = 0;

     while (knockDur > timer) {
         timer += Time.deltaTime;

         if (rb2d.position.x < enemyCollider.transform.position.x) {
             rb2d.AddForce (new Vector3 (knockbackDir.x * -100, knockbackDir.y * knockbackPwr, transform.position.z));

         }

         if (rb2d.position.x > enemyCollider.transform.position.x) {
             rb2d.AddForce (new Vector3 (knockbackDir.x * 100, knockbackDir.y * knockbackPwr, transform.position.z));
             
         }
     }

     yield return 0;

 }

in the BaddieCollider I have this

public Rigidbody2D enemyCollider;

and in the Start() of BaddieCollider

enemyCollider = gameObject.GetComponent ();

I also just noticed he isn't actually being moved on the x axis anymore but still faced in the right direction upon the collision.