Custom theme problem!!

Hello. I’m coding my first wp theme and I’m quite new at it. So I have a problem. I’ve made the home page and I created a custom_post_type and that’s working fine. When I hit a link of one the pages of my custom post_type it goes to single.php correctly. The problem is with the normal pages. The pages post_type that comes originally in wp. I’ve made a few of this pages and I’ve used them for my menu. The problem is that when I hit one of them it doesn’t go to the page content and it opens the homepage instead, with the page permalink. Can anybody help me please?