You are experiencing symptoms that you should not have after a stent procedure. You should contact your cardiologist for an assessment of the current stent implant (could have failed...collapsed, restenosis), or new occlusions. There could be respiratory issues as well.
The cardiologist should have given you information regarding additional occlusions if any
that may be on the border line for stenting or if there are other occlusions not really
ideal for stenting. In a nutshell, if that was your only problem, you should have felt much
better immediately after the procedure. I would question your cardiologist because there
may be another problem that has been overlooked or maybe further investigation is required.