Checkpoint script problem

So I'm making a checkpoint script with empties in the game that are represented by GameObjects spawn, checkpoint1, checkpoint2, etc. The player respawns at the checkpoint, however they get stuck there and they can't move or fall. I checked with my teacher and they couldn't find exactly what the problem was either. I'm thinking that maybe the player is somehow snapping to the empty and being pinned there, as the movement script still functions, but the player doesn't move. Please let me know if you think you know what the problem could be, any input is appreciated. Many thanks!

bool alive=true; Vector3 spawnPoint;
int numberDeaths; public GameObject playerExplosion; float timer; int checkpointNumber; public GameObject checkpoint1; public GameObject checkpoint2; public GameObject spawn; bool death; Renderer[] playerMesh; public float offset; public GameObject mesh;

 void Start()
 {
     checkpointNumber=0;
     alive=true;
     death=false;
     GameObject spawnObject = spawn;
     spawnPoint = spawnObject.transform.position;
 }

 void Update () 
 {
     //playerMesh = GetComponentsInChildren <Renderer>(renderer.enabled);
     if (death)
     {
         if (checkpointNumber==0)
         {
             if (alive)
             {
                 GameObject spawnObject = spawn;
                 transform.position=spawnPoint;
                 spawnPoint = spawnObject.transform.position;
                 death=false;
                 timer=0;
                 collider.enabled=true;
             }
             if (!alive)
             {
                 timer += Time.deltaTime;
             }
             if (timer > 1.3 && !alive) {
                 GameObject spawnObject = spawn;
                 spawnPoint = spawnObject.transform.position;
                 transform.position=spawnPoint;
                 alive=true;
                 timer=0;
                 death=false;
                 collider.enabled=true;
             }

         }
     }
     if (checkpointNumber==1)
     {
         if (alive)
         {
             GameObject spawnObject = checkpoint1;
             transform.position=spawnPoint;
             spawnPoint = spawnObject.transform.position;
             death=false;
             collider.enabled=true;
         }
         if (!alive)
         {
             timer += Time.deltaTime;
         }
         if (timer > 1.3 && !alive) {
             GameObject spawnObject = checkpoint1;
             transform.position=spawnPoint;
             spawnPoint = spawnObject.transform.position;
             collider.enabled=true;
             death=false;
             alive=true;
             timer=0;
         }
     }
     if (checkpointNumber==2)
     {
         if (alive)
         {
             GameObject spawnObject = checkpoint2;
             transform.position=spawnPoint;
             spawnPoint = spawnObject.transform.position;
             death=false;
             collider.enabled=true;
         }
         if (!alive)
         {
             timer += Time.deltaTime;
         }
         if (timer > 1.3 && !alive) {
             GameObject spawnObject = checkpoint2;
             transform.position=spawnPoint;
             spawnPoint = spawnObject.transform.position;
             collider.enabled=true;
             alive=true;
             timer=0;
             death=false;
         }
     }
 }
 void OnTriggerEnter (Collider other)
 {
     if (other.tag == "checkpoint")
     {
         checkpointNumber=checkpointNumber +1;
         other.gameObject.collider.enabled =false;
     }
 }
 void OnCollisionEnter(Collision collision)
 {
     if (collision.gameObject.tag == "death") 
     {
         death=true;
         numberDeaths=numberDeaths +1;
     }
     if (collision.gameObject.tag == "boom") 
     {    
         Instantiate (playerExplosion, transform.position, transform.rotation);
         alive=false;
         death=true;
         numberDeaths=numberDeaths +1;
         mesh.SendMessage ("RenderStatus");
         collider.enabled=false;
             
     }
 }