Guinea Pig Shedding?

Well think of it this way, does your hair ever come out?? old hair and damaged hair has to go some where, so that is perfectly normal....unless it is coming out in huge amounts and it is noticable that she is losing hair (bald spots etc) if this is the case maybe take her to the vet, and as for the scratching she probably has an itch....maybe caused by lice you might be able to find a guinea pig product to get rid of these if it is the case, other wise she might just be itchy for nothing as with yourself sometimes you just get itchy, also all the scratching would probably be making her hair loose meaning when you play with her it ends up on you. hope i helped :)