I'm 31m begining to show first signs of hair loss s@ back of my scalp. Does rogain or minoxidil really workk?

Yes, they may. Although, they may work for you, i'd recommend to rule out other possible causes of hair loss such as thyroid disease and/or anemia. If there is none of those, and you exhibit male baldness pattern, you may try rogaine (minoxidil). I'd not go for Minoxidil (oral) as it does have a higher incidence of side effects.