Create alias with paramater in the middle

Aliases do not support positional parameters so you need to create a function (which you can put in ~/.bashrc). If you really want and alias, you could alias that function.

function grepMe(){
    grep "$1" ~/myfile
}

Then, if for some reason you want there to be an alias, you can make one for the function:

alias grepAlias="grepMe"

Alias don't supports parameter but you can write a small script and name it i.e. "filegrep"

#!/bin/bash
grep "$1" /home/youruser/myfile

Copy the script to /usr/bin and you can run it with filegrep argX in the console.