I'm A 56 Yr Old Female And Have Heart Issues

I'm a 56 yr old female and have heart issues triple bypass 2007 and have 4 stents only four mo ago I had SOB and did a heart Catholic and put in last stents did help some but back now at that time they checked my pulmonary artery and that was fine. The trouble I have is like last time I get it not all the time but at least 1x a day from going up 15 stat airs and if I'm kneeing down and getting up I get it., it's gone in 5-6 breathes but those 5 or 6 breathes are very hard to breath I feel I won't get another breath I got all these symptoms after my pancreas transplant any ideas?