Simple Camera Shake. Attach to a camera and run as a coroutine.

CameraShake.cs

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

// Simple camera shake.  To call just attach to camera and from whever you want to 
// call it, do something like 'StartCoroutine(_cameraShake.Shake(0.15f, 0.075f));'

public class CameraShake : MonoBehaviour
{
    public IEnumerator Shake(float duration, float magnitude)
    {
        Vector3 orignalPosition = transform.position;
        float elapsed = 0f;

        while (elapsed < duration)
        {
            float x = Random.Range(-1f, 1f) * magnitude;
            float y = Random.Range(-1f, 1f) * magnitude;

            transform.position = new Vector3(x, y, -10f);
            elapsed += Time.deltaTime;
            yield return 0;
        }
        transform.position = orignalPosition;
    }
}