RewriteRule和PHP：在URL中添加一个新的'？param = yes'

I've got hundred of webpages already created with RewriteRules and PHP

foo.com/section/item/number --> foo.com/section.php?item=number
foo.com/story/number ---> foo.com/story.php?id=number

Now I would like to include an extra parameter for all the webpages

foo.com/section/item/1?param=yes
foo.com/story/34?param=yes

I tried with:

if (isset($_REQUEST['param']))
{
    print "IT WORKS!";
}

It works only with 'foo.com' (the 'index.php') with no RewriteRule.

I tried also by adding QSA to the RewriteRule

RewriteRule ^story/([^/]+) /story.php?id=$1 [L, QSA]

What am I doing wrong? Thank you very much.

I'm not able to test, but I think this will do what you need

 RewriteCond %{QUERY_STRING !&param=yes
 RewriteRule ^/?c/(.*)$ /%1?%{QUERY_STRING}&&param=yes [L]

First this makes sure if a request already has param=yes in it, do nothing, otherwise append either ?param=yes or &param=yes , if the request already has ? in it.