pick up/throw object

1. the script allows me to pick up the ball, but it allows me to do this no matter where on the map i am, and i cannot put the ball down,

2. throw the ball, either, which falls down under the 'dropping'

3. to pick up the ball i need to freeze its position or it will rotate out of my grasp and just fall

4. although the position is frozen the rotation is not, the block will pass through anything with a collider/ rigid body, only while picked up though, but it is cool that it acts similar to a beyblade. to clarify it hits the other thing, we'll say wall, and stops rotating but it will proceed to go into the wall if pushed a little

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script:

using System.Collections.Generic;
using UnityEngine;
using System.Collections;

public class Pickup_Throw : MonoBehaviour
{

 public float speed = 10;
 public bool canHold = true;
 public GameObject ball;
 public Transform guide;
 void Update()
 {
     if (Input.GetMouseButtonDown(0))
     {
         if (!canHold)
             throw_drop();
         else
             Pickup();
     }//mause If

     if (!canHold && ball)
         ball.transform.position = guide.position;
     
 }//update



 //We can use trigger or Collision
 void OnTriggerEnter(Collider col)
 {
     if (col.gameObject.tag == "ball")
         if (!ball) // if we don't have anything holding
             ball = col.gameObject;
 }

 //We can use trigger or Collision
 void OnTriggerExit(Collider col)
 {
     if (col.gameObject.tag == "ball")
     {
         if (canHold)
             ball = null;
     }
 }


 private void Pickup()
 {
     //ball.GetComponent<Rigidbody>().i = true;

     //We set the object parent to our camera.
     ball.transform.SetParent(this.gameObject.transform);

     //assuming you forward is in z-axis, we add some distance to object so you can see it carrying it.
     ball.transform.position = new Vector3(transform.position.x, transform.position.y, transform.position.z); // (4) is how far the ball will be from camera position.
 }



 private void throw_drop()
 {
     if (!ball)
     {
         return;
     }
     //Set our Gravity to true again.
     ball.GetComponent<Rigidbody>().useGravity = true;

     ball = null; // we don't have anything to do with our ball field anymore

     //Apply velocity on throwing
     guide.GetChild(0).gameObject.GetComponent<Rigidbody>().velocity = transform.forward * speed;

     //Unparent our ball
     guide.GetChild(0).parent = null;

     canHold = true;
 }

}//class