So, your back hurts a little. It will loosen up.
The rain has made your joints ache. They need the oil can of motion.
Your neck is sore from falling asleep on the couch. Swinging your arms back and forth just might relax that.
Every injury you have ever had may scream at you its excuse, its argument for inactivity. It will burn or sting and object in some obscure manner at first. Or constantly, like my torn tendons or my over-strained carpenter's back.
Just take that first step. Breath. Step. Breath. Step and breath.
An old car left sitting eventually rusts into place and it takes a bit of work to get it rolling again. Don't give up on the restoration. You are a classic.
Step and breath.