The last couple years on some other site really reduced the amount I commented. I’m not yet out of that initial instinct of just moving on without trying to engage, it just wasn’t worth it a lot of the time over there, had mostly positive experiences here though, experience wise.
There’s a few factors really, your out of shape comment could be one, no offence meant If you’re pushing your lungs, and airways in general, further than usual, and quite literally stretching them, and faster than they’re used to, the extra stretching can cause that feeling. Lessens as you get fitter. If its proper cold, or.dry, and if you mostly breathe through your mouth, or both, the air isn’t a match for the warm humid like air in your lungs and airways…nose breathing is a big thing to improve your running, there’s a great guy whose name I cannot recall who is a massive advocate for nose breathng in runners and how it can massively help your long distance proper too! Includes things about dehydration lessening etc…worth a search for