Session within a session lock?

I have a page on my PHP site that needs to access itself. I open a socket connection and pass in the HTTP request header including a cookie string such as: Cookie: PHPSESSID=766bc531e9185be6b54206c944f258d9 With the session name and id of the user's current session (as I want the request to the web server to utilize the same PHP session). However, if I use the same session ID things seem to lock and the fread's from the socket just don't return any data. Why would there be a lock in doing a request within a request to the same PHP session? Thanks, Steve