I submit my I-485 in March last year and I am still pending for the green card application.
If May, 2014 I can get the green card, do I need to provide more document to USCIS?
-No unless USCIS send you RFE.
For example, the W-2 during the waiting years, (2012, 2013)?-No.
Do I need to do the medical examination again? -No.