mysterious undiagnosed symptoms

[shabang]

Hi, I'm a 35 year old male, 50 pounds overweight, but I do exercise 30 mins 5 days per week (I just eat too much I guess).

Symptoms from at least the past 6 months are:
1) Chronic nausea feeling, kind of like butterflies in the stomach that won't go away, present 60% of the time
2)  Very Lightheaded most of the time
3)  Heavy tight feeling in the center of the chest, occasional difficulty breathing
4)  Feeling of an awkard forceful heartbeat in the same area
5)  Occasional hard palpitations (skipped beats), also in the same area
6)  Feel very sleepy all the time
7)  Regurgitation of food
8) Rarely, areas of skin have become very painful to touch, no rash

Unusual signs I've noticed:
1)  Occasionally my pulse will rest as low as 45, have even seen it in the 30's while deeply relaxed in bed. When this happens I feel very sleepy. One may argue that since I do cardio exercise everyday this is normal, but I have always worked out and my pulse has never rested below 60 before the symptoms started.
2)  I have a very high intolerance to weight lifting (I will feel far worse for many days afterwards). On the same note, my palpitations really get aggrivated by it.
3) Abdomen gets swollen and hard at times.

Tests I've had:
1)  Cardiolite stress
2)  resting echo
3)  chest xray
4)  the usual labs
5)  EGD scope
6)  Gastric emptying scan
Only the EGD showed anything,mild gastritis.

What I can't get past is, how can mild gastritis cause all this, especially the palpitations and lightheadedness?
I get in these very nauseated "weak heart feeling" modes and during this I will often have near syncope upon standing, whereas otherwise I don't.
I have a very hard time accepting this is all from mild gastritis,  but I don't know where else to turn or what further testing I should go after?

[Cleveland Clinic]

The only other test I would order is a Holter monitor, which would tell me if your heart rate is slow during the episodes of nausea and lightheadedness. If so you may benefit from stopping any anti hypertensives including beta blockers or calcium channel blockers. If the symptoms do not improve, then you may need a permanent pacemaker because the symptoms may be due to symptomatic bradycardia.

[shabang]

PS-- Several weeks of double-dose Prilosec has done absolutely nothing for me

[shabang]

1 other symptom I noticed is that the chest discomfort I have will get worse sometimes if I lay in a certain position.  I don't mean as in, positional changes make it better or worse as in chest wall pain... I mean the internal pressure in my chest changes and i consequently feel more forceful / painful pulses deep within in my chest.    alot of this is pulsatile in nature,  like the forceful squeezing/pulsating i feel in my chest.  And with palpitations, I can't Not believe this isn't my heart.

[shabang]

Oh and yes,  I had an abdominal and pelvic CT a year ago for different reasons, that was normal....also had a recent brain MRI

[Momto3]

Has your doctor ever mentioned the possibility of anxiety?  Anxiety can show up in a million different ways, including those which you describe.  

Many people with extra beats (pvcs, pacs) notice that lying in certain positions (particularly on the left side) makes the beats feel stronger, and sometimes more irregular.  Lifting above one's head can also bring on the extra beats.

It sounds like you have had a good workup.  What does your doctor say about the symptoms?