I've been getting into playing barre chords too, I've got small hands and my muscles in my left hand, which happens to be my fretting hand, aren't exactly the strongest so my hand starts to hurt between my thumb and index finger after a while, couple of interesting facts, Tony Iommi who was the guitarist in Black Sabbath, had to wear specially made covers on two of his fingers after an accident with a sheet metal machine which chopped off the tips, Tony was inspired to keep playing guitar after he listened to a record of Django Reinhardt, a gypsy jazz guitarist who was left with two usable fingers on his fretting hand after being burnt in a caravan fire.