first - are you on any thyroid meds? if not i would get your thyroid checked. i had a similar problem before and after taking synthroid. after starting on synthroid the dose was too high and when i would stretch the back of my calf's hurt and prevented me from stretching bending anything that used the calf muscle. good luck.
when i stretch my legs or my uper body i get severe pain like charlie horses i cant stretch at all due 2 pain back/legs. i have been diagnosed with lupus and arthritis i had 2 neck surgeries and both shoulders cleaned out with a tear in my left. the neurologist that done my neck surgery said my spine is a complete mess he perform a full mri of my spine and i have some damage at all levels