why doesn’t theon carry the title of lord? i’m assuming it’s because he was a ward of the starks and therefore couldn’t inherit anything iron islands-related, but a) he’s not in their custody anymore, and b) sandor clegane is now technically the rightful heir to his house since he’s not in a king’s service. is this just a problem within show?
Theon isn’t called a lord because Theon isn’t a lord. The title “Lord” in ASOIAF is given only to the head of a lordly house. (As opposed to “m’lord”, which is used by smallfolk towards any male who looks noble, or “my lord”, which is used by courteous people for any male that looks noble but not knightly.) There are a few exceptions, such as kings (ex: “Lord of the Seven Kingdoms”) and honorary lordships (ex: Lord Varys), but in general heirs of houses and their brothers are not lords, only their fathers. And if they’re not knights (from youth or lack of ability/desire), these sons don’t have any title at all, which is confusing, thanks GRRM. (Especially since noble women and girls are all titled Lady, whether ruling ladies or daughters of the head of house or married to the head of house, even if their husband is a Ser. Except when they’re princesses. GRRM has very few titles in Westeros.)
Regarding Theon, (a) he is not the current head of House Greyjoy – that would be Euron; and (b) at the time Theon’s father Balon died, he had declared himself King of the Iron Islands, and thus Theon was a Prince. (Which would make Asha a princess, lol.) Even though captive, Theon is still a prince, in the eyes of many, including himself and Ramsay (albeit in a mocking way, “I send you each a piece of prince” for example). If Asha manages to use him to depose Euron (or if Euron dies otherwise and Theon succeeds him), Theon would be titled King, of course. For as long as he can keep it; that is, if House Greyjoy stops being kings of the Iron Islands (a Targaryen ruler would insist, most firmly), then he would be Lord Theon of House Greyjoy. Unless it’s Asha who’s somehow ruling Lady Greyjoy. (But she’d probably use Theon as a figurehead, given her experience at the kingsmoot.) We’ll have to see. But right now Theon’s either a prince, or nothing at all.
As for Sandor, House Clegane is not a lordly house, they’re landed knights, for whom the ruling title is “Ser”, not “Lord”. Since Sandor is not a knight, his title is… complicated. Not being in a king’s service has nothing to do with it (being a Kingsguard would be), there can be plenty of lords working for the king – however, Sandor is an outlaw and can’t claim his lands, which makes it more complicated. (Gregor being only mostly dead makes it even more complicated.) But if Sandor could claim his rights as the head of House Clegane, most likely he’d be Master, not Lord, and not Ser. See here for more.
Hope that helps!