undiagnosed chest pains

Hi There
My Name is ryan i am a 20yr old male, i am 6ft 1 and just over 16 stone
I work in front of a computer 8 hours a day, whic is a fairly easy going job, i am not or have ever been a stressed person i am very rarely ill
My Story lol
For the past 8 weeks i have felt terrible, it really really been the worst two months of my life, I will explain my symptoms in full below:
Chest pain/Discomfort

Chest pains
This started about 8 weeks ago when i was lying in bed i had sudden sharp sjootig pains on the left side of my chest, ever since that night the pain has varied. Sometimes it can be a sharp shooting pain, or sometimes it feels like a pressure. It has no specific area sometimes on the left(mostly) sometimes centre sometimes on the right. Some days it wont be as bad as others , and some days it will be bad . on a pain scale i would say at worst it is a 5/10 but normally a 2. I sometimes get like a numb shoothing pain down my arm also, not normally with the chest pain but separate
Palpitations
Now these are really really getting me down, these started the same night as the pains 8 weeks ago, at first I would only have them like once maybe twice a week. But for the past week I have been having them without fail every day and night, my heart speeds up considerably and thumps real hard to the point where you can see my clothes moving. Also last night it felt like it slowed down and my heart seemed to flutter. They are not painfull just extremely freightining and distressing..Why would these be happening?? I have never suffered from them ever before
Other symptoms
Now these symtptoms may not be related to the chest pains at all but I have had these for at least 5 weeks. First of headaches, I have headaches throughout the day which feel like a big pressure on both sides of my head and behind my eyes, it also makes my face feel numb and tingly, BUT it is not numb because if I pinch or poke it I can feel it
Cough, I have had a cough for about 4 weeks and I cough up a greeny yellowish type mucus, I don%u2019t know if this is related to the chest pains, but assume it is because this is normally due to a chest problem
I have spent two night in hospital (on separate occasions) due to this. The first time was like 4 days after the symptoms started, where they did an ecg, blood work, xray, blood pressure etc and all came back absolutely normal.
The next time i went to th ER was like 3 weeks later, in which again they did an ecg, blood work, xray etc which again all come back normal
They prescribed me omeprazole which has not seemed to ease these symptoms
Last week i did a treadmill test and had a 24hr holter monitor, i am still waiting for the results
But my question to everyone is
DO you think maybe i have had an heart attack??if so wouldn%u2019t they have picked this up at er??
Also if i had a life threatening condition wouldn%u2019t something serious have happened by now??
I personally feel that there is nothing else I CAN DO as I have been to hospital twice seen various docs etc, I am at my last wits and lost I just want to be normal again
Thanks