Lipitor is a drug used to lower cholesterol levels in the blood. There is no direct evidence suggesting that it affects muscle flexibility in yoga. However, muscle pain and weakness are known side effects of the drug, which may indirectly affect muscle flexibility during yoga [1]. It is important to note that muscle pain and weakness are rare side effects of the drug and are usually reversible upon discontinuation of the medication [2].

Yoga is a form of exercise that involves stretching and strengthening of muscles. It is a low-impact activity that can improve flexibility, balance, and strength [3]. Some beginner yoga poses that can improve flexibility include the downward-facing dog, the triangle pose, and the seated forward bend [3]. It is important to consult a healthcare professional before starting any new exercise regimen, especially if taking medication such as Lipitor [2].

In conclusion, while there is no direct evidence suggesting that Lipitor affects muscle flexibility in yoga, muscle pain and weakness are known side effects of the drug that may indirectly affect flexibility. It is important to consult a healthcare professional before starting any new exercise regimen, especially if taking medication such as Lipitor.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/
[3] https://www.everydayhealth.com/fitness-pictures/yoga-poses-for-beginners.aspx