Ok Ann, as Ruber said, the first sentence can be correct (but not very clear) but the second one looks incomplete. Between "en" and "aquí" something is missing. Aquí means "here". Translating the second sentence to English it would be : "I'm reading it in this here", a nonsense even in English.

First sentence is correct, the other isn't it. But what do you mean using that? Because you can also say "Lo pone aquí" or "Lo estoy leyendo aquí".