web server - how to choose backend language

I am confused about web servers.

Until now I have only learned HTML, CSS and Javascript, and as far as I know these can "run" on any kind of paid web server.

Now I want to learn some "backend" language, but I am confused what exactly can be runned on web server. And by web server I do not mean my own, but paid preconfigured web server.

So I have following situation:

I have paid for web server ( long ago, before I considered to make anything else than simple web pages ) and in description I can see that it offers :

• PHP
• Python
• MySql
• Perl

I think it is linux apache server ( I do not know much about this so I apologies If I stated something wrong ).

Could this web server run .aspx sites ( programmed in C# ) ? If it is possible can it be managed by me or does hosting company has to approve it ( by configuring it for me ? ). Or can on this site be installed node.js as backend ? What about Python Django ?

So basically my question is, if I choose xxx language/framework/whatever do I have to choose web server accordingly or I can use whatever hosting company I like ?