After typing that last post, I thought it would be easier to just pop over to A&E in my lunch hour and get looked at.
I can now relax as I've been given the all clear.
The Triage Doctor done a few key checks, blood pressure was good, blood oxygen levels were very good at 98%, heart and lungs sounded fine but he decided to get an ECG done to be on the safe side.
Despite the ECG alarms going mental when it registered my resting HR at 45bpm, the ECG was all clear too, so very good news.
The discomfort in my chest is likely caused my some kind of muscle pull somewhere in my chest wall. They done some poking and prodding but couldnt locate anything in particular but that is what they've put it down too.
Relieved isnt the word. Ok, I probably was being over cautious going over there but hey, its put my mind at rest.