Question

1. I hit the chair in front of me.
1-1. I hit the chair in front of myself.
2. I hit the chair before me.
[They are okay. They are the same. By the way, do you use #1-1? A reflexive pronoun is used here.]

3. I hit the chair in back of me. [O]
4. I hit the chair in the back of me. [X]
5. I hit the chair behind me. [O]
6. I hit the chair at the back of me.
[Can we use the expressions except #4? What about #6? Do you use #6? Is #6 the same as #3 and #5?]

Answer 1

One is preferable. One-one is not. Two is acceptable, but not what we would say in the U.S. It seems awkward.

Three and 5 are acceptable. Four and six are awkward. They all mean the same, yes, but three or five are the ways we would say it.