In the United States (and the rest of the world, as far as we know), statins are prescription drugs and not available over the counter. (The UK allows low dose simvastatin pills to be sold “behind the counter" which requires the buyer to talk with the pharmacist.) There have been proposals to change the policy, with many public health authorities called for OTC statin availability The FDA is now entertaining proposals to make statins and other common prescription drugs available for over-the-counter purchase.
Might statins go OTC in the future? Many people are pushing in that direction, but the natural conservatism of the medical world and regulators is providing friction.
Pfizer pursued OTC status for Lipitor following the pstent expiration. In 2015 they announced they were giving up on the effort.
Note that the debate about OTC statins is tied up to some extent with the debate about how widely statins should be used and should they be given to younger people at relatively low risk for cardiovascular disease.
OTC vs. Prescription drugs
New drugs developed by pharmaceutical companies always start as prescription medications. Sometimes new herbal medicines on the market might go straight to over-the-counter status, but the big drug companies make drugs that are sold only by prescription. This is society's way of limiting risk, institutionalizing prudence, and controlling access to what might be dangerous materials. Doctors explicitly control the dosages for the patients to reduce the risk of overdoses. After several years and many (millions?) of patients with experience using the new medicine, the regulatory authorities have enough information to decide whether to allow a drug to go OTC. Drugs that have the potential for abuse or where medical supervision is necessary are not approved for OTC sale.
Several popular drugs have gone this route. Think minoxidil (Rogaine) and loratadine (Claritin). Insurance companies (including Medicare) benefit when drugs move to OTC status as they are generally cheaper and do not require an expensive doctor's visit. Large drug companies may also welcome OTC status as a way of managing their product lifecycle, especially when a drug is about to go off-patent. In Britain, simvastatin is now available "behind-the-counter", although it should be noted that this is different from OTC in the United States as it involves a pharmacist giving advice to and interacting with the patient.