If you have the slightest aspiration to being a singer the best you can do is invest in at least a little coaching. Knowing your vocal comfort zone in musical terms and knowing how to extend it without strain is doing yourself and everybody you sing to a favour, whatever genre. And leeniea: If your throat is sore, you're singing wrongly, not too much. (And coaching will enable you to learn how to put throat into your voice for heavy rock purposes).