Lipitor is a brand name for the drug atorvastatin, which is used to lower cholesterol levels in the blood. According to the Mayo Clinic [2], statins, including Lipitor, are known to cause muscle pain or weakness in some people. The muscle pain caused by statins is known as myopathy, and in rare cases, it can lead to a more serious condition called rhabdomyolysis, which can cause kidney damage. However, the risk of developing myopathy or rhabdomyolysis is relatively low.

A recent study published in the Journal of the American Medical Association [3] found that statins, including Lipitor, can cause muscle pain in some people. The study analyzed data from over 200,000 patients and found that about 10% of patients who took statins reported muscle pain, compared to about 7% of patients who took a placebo. The study also found that the risk of developing muscle pain was higher in patients who took higher doses of statins.

Despite the potential side effects, statins are still considered safe and effective for most people who need to lower their cholesterol levels. However, if you experience muscle pain or weakness while taking Lipitor or any other statin, it is important to talk to your doctor. Your doctor may recommend reducing your dose or switching to a different medication.

Sources:
[2] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013
[3] https://jamanetwork.com/journals/jama/fullarticle/2785419