My scrotum starts to hurt really badly at times, why is this?

Testicular pain: could be different causes. Most testicular pain is physiologic and self limited. however, acute testicular pain can be a sign of serious pathologies like torsion, acute infection ( orchitis), or hernia. If pain is acute and lasts for more than one hour and/or is associated with fever, nausea, vomiting, or swelling of the testis you should go to the closest emergency department.