After shooting a soccer ball i now have a pain on the left side of my right knee just below the joint. what happened and what should i do?

Tough to tell: What were the circumstances of your injury? Did you feel a pop or tear? Are you able to bear weight on the affected leg? The answers to these questions are clues. You may have injured a ligament, tendon, muscle or cartilage. Consider seeing a doctor if you have severe pain, limited range of motion, or are unable to bear weight.