Lipitor is a brand name for the medication atorvastatin, which is used to lower cholesterol levels in the blood. Joint stiffness is a potential side effect of this medication, according to sources [2] and [3]. Statins, including Lipitor, have been known to cause muscle and joint pain in some patients. While joint pain is a less common side effect, it is still possible. If you are experiencing joint stiffness or pain while taking Lipitor, it is important to speak with your doctor. They may recommend adjusting your dosage or switching to a different medication. It is important to weigh the benefits of taking Lipitor to lower cholesterol levels against the potential side effects. As with any medication, it is important to take it as prescribed and to report any side effects to your healthcare provider.

Sources:
[2] "Is Your Cholesterol Medication Causing Joint Pain?" Baton Rouge General, 12 July 2021, https://www.brgeneral.org/news-blog/2021/july/is-your-cholesterol-medication-causing-joint-pai/.
[3] "Statins and Joint Pain: Can Cholesterol-Lowering Drugs Hurt Your Joints?" GoodRx, https://www.goodrx.com/classes/statins/joint-pain.