A muscle strain occurs when muscle fibers are stretched or torn, often due to overexertion or improper movement. Common causes include lifting heavy objects, sudden movements, or sports activities. Symptoms typically include pain, swelling, and limited mobility in the affected area. Treatment for muscle strains usually involves rest, ice, compression, and elevation, often referred to as the RICE method. In more severe cases, physical therapy may be recommended to aid recovery. Most strains heal within a few weeks, but severe strains can take longer and may require medical attention.