I was warming up for a softball game by hitting off a T. While swinging from the right side I felt what I thought was a rock or a ball hit me in the upper thigh on my right leg. In reality, I obviously tore a muscle. The pain, although severe, disappeared quickly to the point I thought I was fine until I tried to run faster than a light jog. That was a week ago and it hasn't improved. Do I need medical intervention or will rest do the job?