Setup htaccess for subdomains

Ran into a problem on the subdomains and domains of the subfolders of the main site.
On main site everything is working correctly.

/p/s/102-kamnya/ – 404 error
/p.php?pl1_id=788 – a request directly via get allows us to derive the desired information

As I understand it, you can configure htaccess for individual folders on the server and invested in them.

You need to first link (404) gave the same result as the second one (with get).
It is important that this does not entail a problem with the admin and the main website.

Does it really make?
If Yes, please write the time and cost of work.

Sincerely, Alex