If you are dehydrated (which it sounds like you are) the quality of your tissues are compromised.
Connective tissue dehydration causes pain because
connective tissue is the supportive scaffolding of the body; when
dehydrated, it can’t support, protect or stabilize the body properly.

Drinking electrolyte water is a band aid to the bigger issue of dehydration.
I’d recommend getting The Right Stuff to address your hydration. It is a NASA developed electrolyte liquid concentrate drink additive.

Restoring hydration and the balance of electrolytes allows tissues to move in the ways they were designed to move and support the body during movement. Once your hydration is back in check your body is able absorb the work you are doing on the areas that need attention.