Hi Alperchino. I'm sure my experience was completely different to yours, but here goes.
Many years ago I owned a chauffuer and courier business. I worked almost 24 hours a day, seven days a week as that's what the business demanded. For the first six months I didn't sleep in a bed and I only catnapped in the car. On one occasion I drove for 60 hours continuously and I only got out to keep refilling the car. I never slept between Thursday morning and Sunday night every week. I never ate a meal at a table but would only grab a pasty and a pint of milk from the garage. I smoked between 80-100 Camel a day as that's what kept me awake and kept the hunger pains away.
After several years I started to get severe chest pains. It felt as if a knife had been thrust in my chest, I couldn't breathe and I couldn't move. All I could do was sit still and move my eyes! It would eventually ease off and then I could take very shallow breaths. In the end I went to the GP - who smirked and laughed when I said I thought I had had a heart attack! "How old are you? People of 32 don't have heart attacks" he scoffed. I had to insist on having an ECG and he huffed and puffed about that, but wired me up. When he saw the trace he stopped laughing and called in another GP and they gave me some worried looks. Then my GP asked me about my work patterns, smoking etc then told me I hadn't had a heart attack - but my body was warning me that I very soon would! He said my chest pains were caused by severe stress and if I didn't stop working the way I was, start eating properly and stop smoking, then I would never see 40!
I couldn't stop working at the time but in the end I sold my business when I was 36, paid off the mortgage, stopped smoking overnight when I was 39 and I put on seven stone in weight. I'm 50 this year so I did something right!
It might be that your chest pains are the result of something similar Alperchino. As I said, it might be something very different but I did have to insist that I have an ECG. The GP wasn't happy to do that and he scoffed and huffed and puffed but at least he changed his tune when he saw the result. Don't let your GP put you off as many will palm you off if they can. Insist that your GP give you an ECG and keep going back and insisting you have a problem if you don't have much joy at first. After all, many NHS staff seem to lose sight of the fact it's the patients' NHS - not the staff's! They are employed to be there for you!
Good luck.