More of an experience we all will have. Back and knees are notorious for being whiny little bitches long before someone actually gives up on doing physical things.
(if you want to prolong it as far as possible, exercise and stretch before you’re climbing up hill to regain normal levels of mobility!)
Yep! Keep at it. As long as you’re not over-stressing things on a continual basis, it DOES get better with consistent exercise/stretching.
Also the continue moving thing is very wise to notice: keep at it, or your body WILL find a way to be a lazy fuck.