i followed this : http://pimylifeup.com/raspberry-pi-mysql-phpmyadmin/
but when i open 192.168.0.98/phpmyadmin it says The 192.168.0.98 page isn’t working 192.168.0.98 is currently unable to handle this request. 500 so whats the error ?
If you get a "500" error, you should check the error logs on the server to see what it is.
For Apache that will (usually) be /var/log/apache2/error.log
I'm not sure about those instructions. I'm sure I've never had to edit any files to get PHPMyAdmin working on Raspbian. Just installed it, restarted Apache and that was it.