"Ma chaise est où?" is not
correct formal. If you want to ask a question, you need to inverse the verb and the noun : "Où est ma chaise?", like you said.
You can ask questions without the question mark, these are called "Phrase interrogative passive (ou indirecte)" or something really close to that. For example : "J'aimerais savoir où se trouve ma chaise." is a question, "without a question".
If you want more advice regarding "est-ce que", you can follow this link.
"Où est-ce que tu vas?" and "Où est-ce que ma chaise est?" are both incorrect. In a direct interrogation sentence, as I said earlier, verb and noun need to be reversed. It is not the case here, as "tu" comes before "vas" and "ma chaise" comes before "est".
We could try to flip this direct interrogation to an indirect interrogation, but in this case, as pointed in the link I... linked.. earlier, you cannot use "est-ce que" in an indirect interrogation.
The correct syntax is therefore : "Où est ma chaise" and "Où vas-tu?".
Obviously, this is the formal grammar, but in everyday's life we use pretty much all of the formulations given in the answer.