The click handler that you are trying to trigger is most likely also attached via $(document).ready(). What is probably happening is that you are triggering the event before the handler is attached. The solution is to use setTimeout:
$("document").ready(function() {
setTimeout(function() {
$("#link_to_content").trigger('click');
},10);
});
A delay of 10ms will cause the function to run immediately after all the $(document).ready() handlers have been called.
OR
use trigger in call back function of .load();
you can also use .on() instead of trigger()
$('div_to_load').load("#link_to_content",function(){
$("#link_to_content").trigger('click');
});
.on() example
$('div_to_click').on("click",".title",function(){
alert('sdfdsf');
});