Left Nostril Blocked, Cannot Breathe Properly, Lost Sense Of Smell. Costicosteroid Spray Helps Little. Solution ?

Hi,
I am having issues with my left nostril. have had difficulties breathing in the past and used a costicosteroid spray it helped temporarily but was just before i had a kickboxing fight (it was fine straight after aswell) Now about a year later i am struggling to train properley as i cant breath properly. it feels like 1 side is blocked and i am left gasping for air. its making it hard because im a pretty fit person but struggling to train properly. i have noticed very small swelling under my left eye and its tender to touch. also if i get any punches to the face when training my nose runs like crazy. ive also lost some sense of smell. i eat pretty healthy and dont take contraceptive pill as was giving me blood pressure a little while ago.