Mucus Formation In The Larynx Area. Difficulty In Talking. Had Sinus Surgery. Need Help

Hi. i have thick mucus in my larynx area constantly and it ruins my life. i cough constantly but it is very rarely productive. it interferes with my voice also. i had sinus surgery to no avail. I have recently quit smoking , but this problem has been around for about 5 years. When i breathe in, i feel a dry, raspy obstruction on the right side of my throat which causes me to try and cough the discomfort away. When i cough hard enough, my throat closes cutting out the air expulsion and sound of the cough. When it doesnt go i just end up really depressed and worn out with always feeling ill. I am generally unwell, always pick up viruses andinfections, weight gain, poor appetite and low mood. Please help as I feel i cannot carry on like this. Thanks,