Lipitor, a commonly prescribed medication for lowering cholesterol levels, belongs to a class of drugs known as statins. While statins like Lipitor are generally well-tolerated, there have been reported cases linking statin use to muscle-related side effects. These side effects can range from muscle weakness to more severe conditions like rhabdomyolysis, a rare but serious muscle disorder. The impact of Lipitor on muscle flexibility specifically is not extensively documented in the sources provided. However, it is known that muscle-related side effects can occur with statin use, which may potentially affect muscle flexibility. It is advisable to consult with a healthcare provider if you experience any muscle-related symptoms while taking Lipitor or any other statin medication.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/
[3] https://digitalcommons.wku.edu/ijesab/vol12/iss1/33/