keyboard shortcuts issues with left arrow

I have a problem with iTunes keyboard shortcuts : command + shift + left arrow: i can't slow move backward using the shortcuts from my keyboard "I am using a mac" and I tried the same on my pc and it only goes forward not backward.

The problem I am listening to a lecture and I need to write it down and I need to frequently move backward using the keyboard shortcuts because the speaker talk too fast.

Please help me get this fix, I assumed it is a bug in iTunes because I used before and it works fine now it doesn't thank you.