Most muscle strains (pulled muscles) are caused by overstretching muscles. Strains may be minor or severe, such as a torn muscle or tendon.
Symptoms of a muscle strain can vary depending on how severe the strain is and may include:
Recovery time for a muscle strain can vary depending on a person's age and health and the type and severity of the strain. While a minor strain often heals well with home treatment, a severe strain may require medical treatment. If a severe strain is not treated, a person may have long-term pain, limited movement, and deformity.
WebMD Medical Reference from Healthwise