Physical Creative Writing

I am taking a creative writing class in college and the topic of choice for this semester is short fiction. Perfect, because I love fiction and I love making things up. I wish there was a bit more freedom, but we do have prompts and they're pretty much like guidelines. I just hate the idea of thinking more than I have to, but prompts are good, there will be flow and yet surprises.

Anyway, my professor wants us "show" physical feelings. Not emotional because those come easy to me because Lord knows I feel way too much, but physical descriptions have always alluded me. Even in real life when someone asks me to describe I person, I cannot. I say the generic things like "they have brown hair," "they have light brown eyes", or "they're tall". That doesn't really help distinguish a particular person from the rest of the crowd. I can say "they have green glasses" or "they always wear a maroon jacket", things like that but if its how the nose is shaped or how deep set their eyes are, I can't. Physical descriptions are hard to write down.

"Showing" the physical in fiction is hard. We had to write a gory, violent scene for our assignment and I create whole back stories to help me get it all out. Well, in class we did an exercise where we had to describe a violent, gory scene involving a chicken. Let's just say everyone went straight to the point while I created a back story about the chicken. I created an emotional connection to the chicken which made it even harder for me to butcher the poor bird in my mind. So I kept the gory details to a minimum and let's just say I failed the whole point of the exercise completely.

Why do I keep creating back stories? This is short fiction, there is not enough time to talk about their life goals, childhood memories, or dreams unless it is vital to the plot of the story. I just need to stop taking a panoramic approach to the stories. I need to stop starting from the general and going into the specific. I need to start in the specific and stay there. I'll get the hang of it. No back stories. Just what is vital to the movement of the plot.