Movement stops working randomly

Hi, I'm developing a maze game and currently I'm working on coding the player. So far i've created a simple maze in which the player moves around. I've taken a few snippets from here and there.

The player moves forward until it reaches a collider, when it stops. I've used AddForce since the camera moves and rotates with the player so the world axis won't help.

 #pragma strict
 
 var rotateCounter : KeyCode;
 var rotateClock : KeyCode;
 var forwardMove : KeyCode;
 
 function Update () {
     if (Input.GetKeyDown(forwardMove)){
         rigidbody2D.AddForce(new Vector2(transform.up.x*700, transform.up.y*700));                                  
    } 
 
 if (Input.GetKeyDown(rotateCounter)) {
 rotateLeft();
 }
 if (Input.GetKeyDown(rotateClock)) {
 rotateRight();
 }
 }
 
 function rotateLeft() {
 for(var i = 0; i<90; i+=2) {
 yield;
 transform.Rotate(0,0,2);
 }
 }
 
 function rotateRight() {
 for(var i = 0; i>-90; i-=2) {
 yield;
 transform.Rotate(0, 0, -2);
 }
 
 }

In a separate file, i've added the collision controls

 function Update () {
     if ( rigidbody2D.velocity.magnitude > 1 ){
         Debug.Log("Moving");
         var MoveScript = GetComponent.<MovementScript>();
         MoveScript.enabled = !MoveScript.enabled;
     } 
 }
 
 function OnTriggerEnter2D(other: Collider2D) {
     Debug.Log("Collision");
     //The commented solution works fine too to stop the player
     //rigidbody2D.AddForce(new Vector2(transform.up.x*700*-1, transform.up.y*700*-1));
     rigidbody2D.velocity = Vector3.zero;
 }

The second file disables any input until the player reachs a wall in order to prevent rotations in the middle of a run and here comes my problem. I can wander arond a few times and then suddently stops working. My input doesn't come back so the game "freezes"

I don't want to add rigidbodys to the walls since the colliders are a few pixels separated from the "physical" walls.

What can make my code stop working? Thank you in advance for your help :)