The answer is "a pulled muscle".
A muscle strain, or pulled muscle, happens when your muscle is overstretched or torn. This typically happens because of weariness, abuse, or ill-advised utilization of a muscle. Strains can occur in any muscle, yet they're most normal in your lower back, neck, shoulder, and hamstring, or, in other words behind your thigh.
These strains can cause torment and may restrain development inside the influenced muscle gathering. Mellow to direct strains can be effectively treated at home with ice, warmth, and calming prescriptions. Serious strains or tears may require therapeutic treatment.