German Shorthaired Pointers

Hello all, I just joined this site and saw it is very cool. I am the proud owner of a german shorthaired pointer ( All liver color) She just turned 2 in September, I have 2 other dogs also one is a chocolate lab and the other a german sheppard. They all get along fantastic. Ok here is my problem, My pointer is always digging and scratching at herself. Not fleas because i never see them on her, She has a very soft coat , but constantly scratching. Any ideas of why and what i can give her. Had her to the vet but he couldnt find anything either. Also She just turned 2 and she has only been in heat once. and that was back in January, Is this normal? she was in heat for about 3 weeks the one time and nothing since then, Thanks Tammy