According to the sources provided, there is no evidence to suggest that Lipitor can improve flexibility like stretching. Lipitor is a medication used to lower cholesterol levels in the blood [1]. On the other hand, stretching is a physical activity that helps improve flexibility by increasing the range of motion of the joints [2]. While Lipitor may improve cardiovascular health, it does not directly affect the muscles or joints, which are the main components involved in flexibility [3]. Therefore, stretching and other physical activities remain the most effective ways to improve flexibility. It is important to note that before engaging in any physical activity, individuals should consult with their healthcare provider to ensure that it is safe for them to do so.

Sources:
[1] Drug Patent Watch. (n.d.). Lipitor. Retrieved from https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] Everyday Health. (2018, August 7). How to Become More Flexible — Because Yes, It's Important. Retrieved from https://www.everydayhealth.com/fitness/how-become-more-flexible-because-yes-its-important/
[3] NCBI. (2012, October 11). Stretching: Mechanisms and Benefits for Sport Performance and Injury Prevention. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/