According to the sources provided, flexibility loss is not a common side effect of Lipitor (atorvastatin). Lipitor is a medication used to lower cholesterol levels in the blood. The first source, Drug Patent Watch [1], does not list flexibility loss as a known side effect of Lipitor. The second source, a study published in the US National Library of Medicine [2], states that muscle pain and weakness are the most commonly reported side effects of statins, including Lipitor, but does not mention flexibility loss. The third source, an article from Harvard Health Publishing [3], also lists muscle pain and weakness as common side effects of statins, but again does not mention flexibility loss.

It is important to note that while flexibility loss is not a common side effect of Lipitor, muscle pain and weakness are. If a patient experiences these symptoms while taking Lipitor, they should consult with their healthcare provider. The provider may adjust the dosage or switch to a different medication to manage the symptoms.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/
[3] https://www.health.harvard.edu/pain/managing-statin-muscle-pain