"Do you love me?"
Not exactly, but the thing is, that this sentence is just three words long. And putting the personal pronoun (in a function other than the subject of the sentence) at the beginning of the sentence is weird on the border of just wrong.
In this particular sentence, the only really natural question is "Kochasz mnie?" (and "Kochacie mnie?" if you really feel the need to ask it in plural 'you').
Then, you can of course use the question-making "Czy", and then it feels a lot better if you specify the subject: "Czy ty mnie kochasz?" is definitely better than "Czy mnie kochasz?". "Ty mnie kochasz?" definitely looks like a surprised "What?! You love me?!". And "Mnie kochasz?" is just too bad to accept.
Not exactly. Take a look at the declension tables here: