Never underestimate the power of the mind over the body, it is phenomenal. Stress causing chest pain is common enough, the pain leads to fear, hyperventilation, and you get a vicious circle of positive feedback. It is so good when it is over, that you "come down" with relief - and maybe hence the cold and weakness. However, it could also be a viral infection? I once had severe chest pains at a time of mega-stress, and panic set in. I went out and ran 6 miles reasoning that a dying man would be unlikely to be able to run 6 miles! A plethora of protean symptoms followed over many weeks, pain here, pain there, hot, cold, sweating, you name it I had it. I never had it investigated, and it slowly abated, but it does re-emerge every now and then to annoy me even years later.
I am convinced it was a ********** virus or similar, and it lurks long-term in the tissues.