Dude, I know the feel. While I'm pre-everything, my voice apparently comes out monotone and with little inflections despite the fact that I think it does. I just make an attempt to stress inflections and I ask friends and family to let me know if I an monotone or coming across with more of a variety. I think if you actively practice, you may get better results. Of course, it always helps to listen to a recording of your voice. I now use an app called Vox that is like a walkie-talkie kind of thing, and I listen to the audio I send so I can gauge how my voice came across versus how I think it came across.