low blood pressure & large difference in left/right readings

I am 38 and overweight, heart disease runs in the family, on metoprolol for high blood pressure for 3 years and have had chest pains coming and going for the last year and a half.  I take my BPdaily and although it averages a little high (136/84)- I have had some readings where my left and right arms had a large difference but it's never consistant.  But in the last couple of weeks I have had 2 different times where my right arm reading plunged.  left138/83, right77/66 pulse62 and left126/84, right 46/30 pulse 56. I felt normal. I want to believe this is the monitors fault but batteries are fresh and I'm worried because it's the right arm both times and the pulse read correctly.(My pulse is usually low like that.)  I have run the gamut of heart testing...nuclear stress test fine, ecg fine, ct scan fine, holter monitor revealed pvc's and some low pulses but my dr. not worried.  He thinks I might have mvp and I do notice palpitations. Only other wierd thing is that my lips turn bluish sometimes. Can these readings be real or would I be dead if they were?

[amdgjoseph]

I should add that I've recently been diagnosed with gallstones which could (hopefully) explain some of the chest pain - hoping that once I get that taken care of that the chest pain goes away.  But I'm worried about scheduling the surgery for it with a possible heart condition in question.