Stomach pain/acid causing chest pain

I'm new to this forum, but desperately seeking reassurance!
At the start of August I started feeling unwell-I visited my doctor who felt my stomach and said it was possible gallbladder problems & would arrange a scan. About 2 weeks later I started suffering with heart palpitations. I had them all night & didn't sleep a wink & thought I was going to drop dead.
My own doctor checked me out & said chest, heart etc was all ok. I did however have blood in my urine and kidney pain.
A couple of days later I felt really unwell and ended up in hospital with stomach pain. 2 days later I had a scan which showed no gallstones but gallbladder slightly distended. Bloods etc all fine.
I was allowed out on day 4 as I was coping with nausea and pain and told I would need a gastroscopy. I was started on omeprezole.
The heart palpitations continued, but didn't show on ecg, although my doctor said I had an ectopic heart beat.
This weekend I've been feeling a bit light headed at times and tired, but not too bad.
Today however I got an excruciating pain in the centre of my chest. It lasted for about 8/10 seconds and then stopped. It did it about 30 minutes later.
I came home from work feeling unwell and about an hour later it did it again. The doctors said they'd see me-did ecg-all OK, chest etc all ok. They said it's probably related to stomach problem (maybe inflammation/maybe ulcer.)
Since then it has happened 3 more times. Have been drinking gaviscon just in case!
I'm at my wits end feeling crappy (6 weeks now.) On a low fat diet, no caffeine, no alcohol and have lost 1 stone 11 lbs since the start of August.

Just seeking reassurance really, particularly with the pain today. Feeling really down & fed up