Basically I've had the flue for the past 5 days and since yesterday have developed a nasty cough and can't seem to get rid of it, I even concentrate and try not to cough but still cough …

As nasty as it may be i also cough up mucus every now and then and i imagine that to be flu-like side effects, And it's bad because the cough hurts because im coughing so hard that it hurts my braincells lol, and gives me a headache until i take relief pills.

Is there any food/Pill or technique known that i can use to help myself stop coughing? I honestly had no idea coughing could be this bad

Sounds like you could have a chest infection, don't leave it too much longer before you see a doctor,Mine always eases with steam as it makes the mucus easier to cough up and stops that awful dry cough.
try a steamy bath or a bowl full of hot water with a towel over your head ….breath in the steam.
Turn your heating right down (and put a jumper on) as heating will dry the air too much , put some bowls of water around near the radiators (if you really have to keep them on) to increase the humidity
I dont find cough remedies help.
If it carries on or gets worse see your doc straight away.