I don't see all of the pm's ive sent in my sentbox. What am I missing? I'm also not able to access pm's that were previously sent to me in my inbox once I read it. I checked the trash folder as well and found nothing.

If you get a reply to a PM you sent, it will be moved from the sent box to the in box. All PM's are automatically deleted 60 days after the date of the original message. If you have messages you want to keep past the 60 day point, you must move them to the saved box.