Lipitor is a brand name for the drug atorvastatin, which is a type of medication known as a statin that is used to lower cholesterol levels in the blood [1]. According to the Mayo Clinic, one of the potential side effects of statins is muscle pain or weakness, which can range from mild discomfort to severe muscle damage [2]. Cleveland Clinic also confirms that some people who take statins like Lipitor may experience muscle pain or weakness, which can sometimes be alleviated by making changes to the dosage or switching to a different medication [3]. Therefore, it is possible that Lipitor can cause muscle pain or weakness as a side effect, but it is important to discuss any concerns about potential side effects with a healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013
[3] https://health.clevelandclinic.org/statins-giving-you-achy-muscles-ask-your-doctor-about-these-4-potential-fixes/