What Does Shortness Of Breath Along With Pressure In The Chest Indicate?

If I have an EKG, chest xray, nuclear stress test, and ST scan and all show no obvious blockages, but I still get shortness of breath after very little exertion, have heaviness on my chest, headaches and a bit of nausea after little exertion, would you recommend a heat ctheterizaion to detect possible blockages in small arteries? My sister slso passed all these same tests but insizted on a catheterization and had emergency triple bypass procedures thar same eve. Our family history is riddled with cardiac problems. Thank you.