Chest pain when excited / stressed, left arm and armpit pain

I've been trawling message boards for the past few months now when I get symptoms, so I thought it was about time I posted myself. I'm a 34 year old male, 6ft and 230 pounds. Although I'm overweight I am very active and run 10 miles every Sunday and run 4x 2.5 miles runs in the week. On top of this, I played 5-a-side football weekly, but in the past few months I've had to put a stop to this. I'm currently on a low fat diet and have already lost 3/4 stone, so I hope to get my BMI back under 25 soon. My cholesterol is currently 6.7 which I’m taking steps to lower (low fat diet + remove fatty proteins + plant sterols).

I seem to get pain over my left pectoral chest again whenever I get stressed, this pain often manifests itself in left arm pain, originating from the underside of my elbow. The pain in my chest appears to be a numb pain, around the breast bone. I would NOT describe it as constricting or limiting me to breath. Although it does scare me and prompts me to stop whatever I'm doing and take a break (if at work). I often get left shoulder pain when driving to work (which take about an hour) and this often radiates into my chest and arm. To rectify this I now only drive twice a week, and catch the train the other days.
Occasionally I get a very sharp pain over my heart area (9/10) which completely stops me in my tracks. This pain actually doesn't come at times of stress, and can happen at any time, although the last time it occurred my left elbow was raised on a chair which makes me suspect TOS. From what I read, heart pain does not manifest itself as sharp pain, which I take some comfort in. The strange thing is when I go for a run I don't get the symptoms and I find it very relaxing. However if I play football (some of you may call this soccer), I can often be shaking at the end of the game.

However I also get bad chest pains after a heavy meal which doesn't fall into the symptoms of TOS. I've had a camera down my throat (twice in fact) to check for anything abnormal there, and nothing was found. I've had a 24 hour ph study (with a probe down my throat) which showed only normal readings.

In general I don't wake up with chest pains, but they often come about mid morning.

Since January 2011 I've been able to feel a strange sensation under my left armpit, it comes and goes but it can be felt everyday. Recently (it is now Oct 2011) this feeling is with the majority of the time, it often is felt once I've been awake for 30mins or so.

Living in the UK, we have free medical care through the NHS but I also have private medical cover. So far I have had several EKG's and I have also had a cardiac CT coronary angiogram (where the dye they put into my arm caused me to have a nosebleed) and MPI (radio active dye and test at rest, week later same again but before the test I run on the treadmill). All the tests thus far have been negative which is a relief but it doesn't give me a way forward. Any advice on here would be appreciated and I will try to keep every updated on my progress.

I would like to add that I'm not a traditionally stressed person, I generally take things as they come in a laid back way. I actually have no reason to be stressed, apart from the chest pain itself.

I'm planning on running the Birmingham half marathon in a few weeks and my cardiologist says he knows no medical reason why I shouldn't run.

When I have trawled the net, I have taken comfort in reading other peoples blogs/messages when I can see how the case is progressing. I will hopefully report back as I get the results from my tests and if the symptoms get worse.