Frankly, I'm guessing.
It would seem that the duration of your seesion was longer than normal and more challenging. I would suppose therefore that you put some "strange" stresses on your body to which it may now be reacting.
Several nights ago, I left the AC on in my house all night and had a shoulder exposed to the cool breeze. All that day I felt some stiffness in it. No exercise involved, just an odd temporary set of conditions. After time all returned to normal.
I certainly hope you are not actually injured and that all returns to normal for you quickly.
And, I wish I had the fortitude to undertake such a ride myself.
Carl
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Just Peddlin' Around