Collision check

As many here i would like to share my problem with you all and if possible get some help or refernces. I'm almost finishing my first game in Unity wich is a simple maze with character collecting different coins.As it was a hassle to put manually all the different coins in the terrain i decide to try an make a random generator for the coins(Wich somehow i managed to do after a lot of research).The script is working doing what i'm asking it but the problem is that it's spawning objects most of the time inside walls.So i tried to add rigidbodies to coins and it;s messing with the coins position as the coins have a script for rotation,not to mantion that i have the coins collision triggered because they do a certain action when colliding with the character.So after some research again i saw that i need to check in my generator script a near object collisions and somehow change the spawn position of the coin if it's true.I'm trying to figure out how i can do that as my skills in C# is less than ok.My script is attached to my terrain and it looks like this:

using System.Collections; using CustomArrayExtensions; using UnityEngine;

public class ObjectSpawner : MonoBehaviour { [SerializeField] public GameObject[] letters; GameObject selectedObject; private int amount = 0; public int limit;

 void Start()
 {
     StartCoroutine(SpawnObjects());
 }


 IEnumerator SpawnObjects()
 {

     selectedObject = letters.GetRandom();

     while (amount < limit)
     {
         Instantiate(selectedObject, new Vector3(Random.Range(35.0f, 950.0f), 9.0f, Random.Range(35.0f, 950.0f)), Quaternion.identity);
         yield return new WaitForSeconds(5.0f);
         amount++;
     }
 }

 void OnCollisionEnter(Collision col)
 {
     if (col.gameObject.name == "Fox_Main")
     {
         Debug.Log("Collision Detected");
     }
 }

}