complete heart block, high LDL, low HDL, and sometimes a mild pain in the left side. Is it a sign of impending heart attack?

I am 39 years old, male, and 168 cm in height, had had a second degree AV block, and hypothyroid two years back.  Recently I was diagnosed with 3rd degree AV block. total chol 228, LDL 156, HDL 38, Trig 169, VLDL 34 and TSH 9.85. I never got any symptoms before. However today, I felt a mild pain in the left side, below nipple region. it lasted for a few minutes only. My maternal grandfather died in heart attack. One of my paternal uncles also died in heart attack at an early age.
My doctor advised me to go for an angiogram and pacemaker implant.

Is this pain related to any blockage? Or it has a connection with complete heart block? Is this pain a symptom of impending heart attack?
I will be highly obliged if you kindly answer my query. Thank you in advance.