So i been having a slight issue with MOH.

I bought the game pre-owned so never got a serial with it or anything tho when i play online it says verifying online pass or something like that then closes out of the game. The weired thing is it would work fine a few weeks ago now all of a sudden doing this. Anyone ever have this issue before? I hope i don't have to buy a serial or anything would really blow :(

I think you need and EA account don't you?
I wouldn't really know bout ps3 but for Xbox my GamerTag is linked to my EA account so if i ever need and EA account to play a game it just logs me in automatically.
Try the EA web site

It's probably trying to set you up with DLC maps hence the message as from my understanding the Online Pass for MoH only applies to DLC, not the ability to play online so as long as it's the stock content in rotation it should work.

If you read the FAQ it only mentions DLC: http://www.ea.com/1/online-pass-moh-ps3