HI Hearty! I have the same problem as you.
When I go to the doctor my bp is 160/100, sometimes higher. When I take it at home it is sometimes as low as 96/63. I just freak when I'm going to see the doctor, even when nothing is wrong. I do have high blood pressure (it runs in the family) so I take meds to lower it. The meds are what has caused my GERD.
I too also have had the shoulder and chest pain in my left side. Mine was worse in the morning when I got up after sleeping on it. It seems to be gone right now, but when my gerd is acting up it is worse. I have had an ekg, nuclear stess test and echo. My cardiologist said everything is fine. I would still mention it to your doctor, or go see a cardiologist. That's what I did to try and settle down. I think stress from worrying something is wrong makes you think something really is wrong.
Since I have switched from Nexium to Aciphex my chest pain seems to have gotten much better.