What Causes Difficulty Breathing Despite Being On Patches For Tobacco Addiction?

2 weeks ago I had a heart attack,i had a stent put in.I decided then to stop smokeing and I am on my 14th day with patches.But I am still finding it hard to breath deeply and have a slight pain in my lung area front and back I am doing as I have been told but am worried is this because I have stopped or is it another attack on its way?I feel ok apart from this and don t want to start again,I smoked 20 a day since I was 14 and am now 66.Along time I know but better late than never.....