After reviewing the sources provided, there is no clear evidence to suggest that Lipitor, a medication used to lower cholesterol levels, can affect flexibility during stretches.

The first source [1] provides information on the drug patent for Lipitor, including its chemical composition and indications for use. However, it does not provide any information on the potential effects of Lipitor on flexibility.

The second source [2] is a study that investigates the effects of statins, a class of drugs that includes Lipitor, on muscle function and physical performance. The study found that statin use was associated with decreased muscle strength and physical performance in some individuals, but it did not specifically examine the effects of statins on flexibility during stretches.

The third source [3] is a review of the literature on the effects of statins on muscle function. The review concludes that while some studies have suggested that statins may have negative effects on muscle function, including muscle pain and weakness, the overall evidence is inconclusive and further research is needed.

In summary, while there is some evidence to suggest that statins, including Lipitor, may have negative effects on muscle function and physical performance, there is no clear evidence to suggest that Lipitor specifically can affect flexibility during stretches. It is always important to consult with a healthcare provider before starting any new medication or exercise routine.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://pubmed.ncbi.nlm.nih.gov/30511410/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/