The majority of the stretch exercises feel painful after waking up although they are easier to do during the daytime (or a certain while after waking up). Why does this happen? I think the muscles are tight during sleep, therefore it takes a while for them to loosen up after sleep.
One thing that happens during sleep is that your body temperature drops a bit, which is why we really prefer to be covered when we’re snoozing. Cooler temps might be causing muscles to be a bit stiff, also we’re very still in one position for long periods of time during sleep, that’s not going to encourage flexibility right off the bat.
My understanding is that it’s easier, less painful, and safer to stretch your muscles when they are warmed-up from use (not necessarily from warming them up temperature-wise). When you wake-up you have not used them very much for a few hours, hence the stiffness. I stretch very little before exercise but always when I finish - it’s much easier and feels a lot better.
Thank you so much for the informative replies 