My Domain does not work with www

hello I have a page in WP in the subdomain store.mydomain.com and when I search in google it appears with www.store.mydomain.com but it does not show the page, I put in the .htaccses the following code neither of the two It works.

    # BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS}        =off   [OR]
RewriteCond %{HTTP_HOST}    !^store.midominio\.com$
RewriteRule ^(.*)$          "https://store.midominio.com/$1" [R=301,L]
RewriteCond %{HTTP_HOST} !^www.store.midominio.com$ 
RewriteRule ^(.*)$ "https://store.midominio.com/$1" [R=301,L]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

RewriteEngine On
RewriteCond %{HTTP_HOST} ^store.midominio.com
RewriteRule (.*) http://www.store.midominio.com/$1 [R=301,L]

I have been trying and reading for a while and it does not work for me!