It's most likely because of spam views on the GA account.
You can see it on referrals.
Do not go to the sites you see there as it's only spam and meant to get you there.
It could be viruses.
See here how to get ride of it.
This is the best way, a normal filtering method is not good enough.
Removing spam referrals in Google Analytics doesn't work anymore for some referrers
I see that you have edited your question with: "can anybody explain me how GA is working on getting the page views / clicks per page?"
Google Analytics use javascript to get the views and clicks.
This code:
<!-- Google Analytics -->
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-XXXXX-Y', 'auto'); // <-- this is the ID
ga('send', 'pageview');
</script>
<!-- End Google Analytics -->
Is the part sends the data form your page visitor to GA.
And since javascript is written in plain text, anyone can take your UA-ID.
And that is what the spammers do, they take your UA-ID and create traffic on your UA-ID (not your actual page).
They do this because they want to trick you as an admin to visit their page since it shows up as referal page.
Had the GA-code been PHP the UA-ID would not have been so easy for the spammers to get hold of. But it would also mean a less powerfull GA since you need the users data in a lot of the things.
You can't get the same kind of data about the user in PHP as in javascript.
As I mention in the answer I link to above, you can easily get ridd of all this fake data from GA by adding a dimension. This is a variable that the user sends to GA that you decide.
If the user does not send this variable you know they are not on your page and you can filter out that data.
I hope this helped you to answer the question.