I see.
So when I'm learning to understand Japanese sentence one by one, should I dissect the sentence and understand every part of it, or should I just go with the flow and try to comprehend it as a whole? I am tempted to take it apart. Like, for the sentence I just asked:
Hai, sou desu ga, nanika o-komari desu ka.
I don't know what sou means, I will probably search it and put it back in the sentence and try to make sense of it. And like nanika o-komari desu ka, since I now know that nanika means something, and komari/komaru means "have trouble/be in trouble," and since o indicates that it's, like, the direct object, kind of (well that's what I learnt so far), it makes me think to have trouble with something. Like the something is being troubled. So it's asking them, is there something you're having trouble with? Is that pretty close to "is something the matter/do you need help?"?
So ga can be used in a lot of different ways, not only for a topic the listeners don't know about?
Wait, you kind of lost me at the dialogue on the phone. Nanika go-you demo aru'n desu ka? It sounds kind of slangy with the aru'n. There's already another but because demo means but too, right?