Nerve, Lyme, Panic, or GERD? Help!

May 31st I went to the ER. I had a fullness in my sternum followed by lightheadedness and numbness in my left side. Thought heart attack. (BTW I am 31, peak physical health with a strong fitness regime, history of stroke, heart disease, and bursitis in the family, and my Dad has anxiety)
Had a blood test and exercise stress test done and all showed fine. My doc thought GERD and put my on mediciation.
I am now having more consistent symptoms. I get a numbness just about every other day in my left arm expanding from my shoulder. Sometimes have a sharper pain in my left rib cage. Goes away and comes back without any consistency. I notice myself yawning a lot off and on consistent with a dull soreness in my neck almost like I have to stretch but nothing is appeased. It feels mildly like lifting my shoulder above my head alleviates some of the symptoms.
I almost only have extreme symptoms like the lightheadedness and heavy eyes when I am sitting in my car or on my couch and not every time I sit.
I see a lot online of things this could be but am unsure and am working on getting the docs to try and figure it out.
Any ideas?

[Houman Vosoghi, MD]

You have a lot of nonspecific symptoms that may or may not be related.  Anxiety/stress/depression is high on my list but there could be other more physiologic reason(s) as well.  You need to go see a very good and experienced primary care doctor who can run all the usual tests (thyroid, CBC, etc) and do a full exam and come up with a game plan for you.  Good luck.

HV