Based on the information available, there is no evidence to suggest that stretching while taking Lipitor (atorvastatin) will directly cause side effects. Lipitor is a statin medication used to lower cholesterol levels, and stretching is a physical activity that can help improve flexibility and overall fitness [1].

However, it is always important to consult with a healthcare provider before starting any new exercise routine, especially if you are taking medication. This is because certain medications, including Lipitor, can interact with physical activity and potentially lead to adverse effects [2].

Additionally, it is worth noting that Lipitor has been associated with a range of side effects, although these are typically mild and go away on their own. Some common side effects of Lipitor include headache, nausea, diarrhea, and muscle or joint pain [3].

In summary, while stretching while taking Lipitor is unlikely to cause direct side effects, it is always best to consult with a healthcare provider before starting any new exercise routine.

Sources:

1. Mayo Clinic. (2021). Atorvastatin (Oral Route). Retrieved from <https://www.mayoclinic.org/drugs-supplements/atorvastatin-oral-route/side-effects/drg-20069853?p=1>
2. DrugPatentWatch. (2021). Lipitor. Retrieved from <https://www.drugpatentwatch.com/drugs/lipitor>
3. US Food and Drug Administration. (2016). Lipitor (Atorvastatin Calcium) Tablets, for Oral Use. Retrieved from <https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/021367s042lbl.pdf>