Sprains and strains are common and are the more medicalized terminology for the common phrases of "pulled a muscle" or "tore a muscle." The only difference however is sprains refer to ligaments that have torn and strains refer to muscle and tendon tears. How bad the sprain or strain is will dictate how long rehab will take and whether surgery is needed or not. It's important to seek treatment if either one occur to prevent the sprain/strain from getting worse, and more painful possibly leading to higher medical costs if surgery ends up being needed.