So to answer the common question, Yes this is a common thing on X-Box 360's. It maybe because of the belt in the drives opening mechanism. It either A, have been bumped and moved out of place or B it could be perished and need replacing. If you need any help on how to get to the DVD drive heres a link of a guide:
[guide|3358]
Yes the Guide only gets to the drive itself so you will need to disassemble the drive itself to get to the belt or the problem part. I unfortunately can't find a guide on that but if I do I will link it
Good Luck hope its successful and you can go back to using your console as usual.
cheers ;)