Upper Left Abdomen And Heart Problems ( Palpitations )

Hello,HAving some bad health problems obviously. Dont mean to depress
anyone but i am now in my third year of whatever it is..

Heart palpitations ,stomachache left and right side, pains in arms and neck.dont know what to do.Have been to all the relevent doctors and aprt from some ulceration of my stomach nothing. HAvehad all the cameras in fact there are celebreties that have had less media attentionthan my insides. i am a 31 year old male who does smoke(fool) and am about 16 stfor my 6 ft in height.

It all seems to concentrated in the abdomen and chest area varying from severe pain to general discomfort. I feel unwell all the time ,very tired with absolutely no energy. When it started it was was just in my upper left abdomen just under ribcage but now is all over abdomen.sometimes i feel it going to kill me and that my heart is struggling to beat.All test have shown very little,catscan,endoscopies, ultrasound.I was thinking it might be lung related but have no cough or wheezing.

I get remisions some time but they never last long.HAve been
told to cut stress out of my life but the only thing i stress about is the fact that i am a young man who has been sick for three years. Get terrible weakness nearly allthe time and recently have been finding it hard to even walk short distances.Anyhelp would be greatly appreciated as am my wits end.this is not living and at this stage am hoping for something bad to happen so they might find out what is wrong.

Thanks