A muscle strain is an injury to a muscle or a tendon — the fibrous tissue that connects muscles to bones. Strains can occur in any muscle in your body.
Minor injuries may only overstretch a muscle or tendon, while more severe injuries may involve partial or complete tears in these tissue. Strains often occur in the lower back and in the muscle in the back of the thigh. Symptoms include pain, swelling, muscle spasms, and limited ability to move the muscle. Treatment may include pain medications, ice, splinting, physical therapy, acupuncture or and/or injections.