The shitty weather and the older part along with me always being hot..and also very warm all the time.
So to answer your question I'm fairly sure it's the latter.
Last year I had some suspicious pain in my chest, so I called the emergency number. The medics hooked me up for a heart monitor and found nothing..than they turned the machine on and found a perfect heart beat. Best of the month they said, so Yay!
Prolly stress or something..