私は今音楽を聞いています。(With Subject) Watashi wa ima ongaku o kiite imasu. Or 今は音楽を聞いています。(No Subject, only "now") Ima wa ongaku wo kiite imasu. Both are correct. Hope it helps you. >)

What is the difference between しています and います ?

okay i understand now . thank you very much ありがとうございます。

"ima wa" means something like "at this very moment", so I think it is too strong or emphatic. You can just say "ima", or you can even omit it because it is quite natural that the speaker is listening to music at present.

is it "ima wa ongaku o kiite imasu" ?