45 Yr Old With Heart Problems, But No Results.

I am 45 yr old male who has been having chest tightening from the centre towards my left breast running verticle. Also the pains are into my back, just below the shoulder blade. The tests I have had so far are the ultrasound echo gram, a stress test, the holter montitor, and today I had the mibi stress test with the tracer. Although I have no definates as of yet ( still waiting results of the mibi) the cardiologist says the all things point to a blockage in the backside of the heart. He said that the results of the mibi will reveal the blockage. Of note I am a smoker for 25yrs, and all blood tests indicate a slightly high in the normal range of colestorol. I feel fine when running the stress test with no pain anywhere, and I am able to bike ride and walk distance without problem. I seem to get most discomfort and pains when relaxing. Dr seems to think that there is a blockage in the rear of the heart, and I am stunned and forgot to ask the questions I should have asked. Does anyone have any input or suggestions as to steps to do or things I should ask. I am on plavix for blood thinner, coversyl for blood pressure, and crestor for colestorol, and nitro for emergency relieve. I have gone into major depression over this and I told to just continue the meds and I will hear from dr in about 1 month. Depressed. Thanks!