How did you injure it in football? Where is the pain? What doctor told you to just wear a jumpers strap? Those are worthless btw unless you count the placebo effect they may provide.
Either way they dont prevent the injury from getting worse. Was it a football injury or did it just get sore playing football? These would be important questions to know for a proper diagnosis.
See if you can find a kinesio taping practitioner in your area it works wonders on knee pain and inflammation.