php pages to WP page

Hi, I’ve just transfered to WP and I cannot find a way to “convert” my php pages to WP pages. My php pages contain Google Chart codes which includes HTML + php for the MySQL connection. I’ve been trying plenty of plugins about adding php coding etc. However It’s still not working. The only conclusion I got is that if I “copy/paste” HTML codes in a Custom Field plugin, it works. But in my code, it has php as well. Is there any solution?

Thanks