I know a few reasons that I can think of. Since I started this job, I've gained maybe a stone in weight which isn't great, I've also coincidentally started getting this chest pain and chest tightness. I have seen a doctor about it and they say I'm healthy and there's nothing wrong. When I try and focus on my breathing or stutter a little, my chest pain and tightness usually starts and I haven't had it before the job, at least I haven't noticed. When I stutter, I usually get in a little bit of a panic as it's unprofessional and embarrassing to do. I panic more when I stutter on words I usually don't stutter on. When I see a call type with either of those two words that I cannot say, my chest pain and tightness also starts and my heart starts beating faster too. It's something I'm working on fixing as long as I have this job but I can't imagine sticking to it for years, I'd die from the stress due to the stutter. Apart from the stutter and weight , the job is great, safe, comfortable and has above average pay (it's not much more but its enough for now and my union is planning a strike for higher pay )