Suggest Treatment For Knee Pain

I am 49 yr old white male, I was doing 50 yard sprints with my sons soccer team. I felt and heard a pop in my left hamstring It was approximately 3-4 inches from the back of my knee. I dropped in pain, I cannot walk up stairs and can not sit down. I have a lot of pain trying to flex my leg. I have taken motrin, and started the rice trestment. I am getting a lot of spasm which increase the pain. I cannot put any pressure on the back of my leg and I did get immediate swelling close to the back of my knee. Attempting to walk hurts and flexing my toes towards my knees is excruciating.