In general, you should be on the look out for symptoms similar to your initial presenting chest pain to recur. With a stent, the liklihood of restenosis or a recurrent blockage is quite low. Plavix along with modificaitonof your other risk factors including lowering your lipids ,losing weight, controlling blood pressure and diabetes will all help.
If you have any concerns whatsoever, you should call your referring physician or the interventionalist who did the procedure. Many cardiologists will order a follow up stress test within the ensuing 6 months to assess the success of the procedure.