What should I do? Heart problems or indigestion.?

I'm 29 years old and have been having tightness across my chest that wraps around my left arm and across the left side of my back. I sometimes get a headache and neck pain as well. I get very lightheaded, short of breath and have stabbing pain in the middle and left side of my chest. I went to my doctor and he told me that I have indigestion without running any tests or even taking my blood pressure. I have also noticed that my blood pressure at home is a lot lower that usual (91/54). Should I just trust my doctor or get a second opinion? It's probably nothing but him diagnosing me just by looking at me didn't make me feel any better about what is going on.