Changed the url in general setting then can't access my wp admin pages

Hi,
I am new in wordpress.I install wordpress and also install theme but when did changed my url then I could’t access my admin pages at all.Then I tried to back the previous url it didn’t worked.
After few hours I removed the wordpress from my cpanel and reinstall again.Now Its installed but I can’t access administrative interface.Then I read the forum instruction and tried to change in as following:

Changing the URL directly in the database

If you know how to access phpMyAdmin on your host, then you can edit these values directly to get you up and running again.

Backup your database and save the copy off-site.
Login to phpMyAdmin.
Click the link to your Databases.
A list of your databases will appear. Choose the one that is your WordPress database.
All the tables in your database will appear on the screen.
From the list, look for wp_options. Note: The table prefix of wp_ may be different if you changed it when installing.
Click on the small icon indicated as Browse.
A screen will open with a list of the fields within the wp_options table.
Under the field option_name, scroll down and look for siteurl.
Click the Edit Field icon which usually is found at the far left at the beginning of the row.
The Edit Field window will appear.
In the input box for option_value, carefully change the URL information to the new address.
Verify this is correct and click Go to save the information.
You should be returned to your wp_options table.
Look for the home field in the table and click Edit Field. Note There are several pages of tables inside wp_options. Look for the > symbol to page through them.
In the input box for option_value, carefully change the URL information to the new address.
Verify this is correct and click Go to save the information.

But its not working.Then I did also some changed in wp-config.php from the Edit wp-config.php in the following step:

define('WP_HOME','https://amarshikkha.com');
define('WP_SITEURL','https://amarshikkha.com');

Again its not working then I used relocated method btu it still not working.Now I am very confused.How can I develop my site.Please someone can help me to overcome from this problem?
Thanks