Sting's wrestling career is over ... TMZ Sports has learned.
Long story short ... the wrestling legend messed up his neck real bad at his "WWE Night of Champions" match against Seth Rollins back in September -- and was never able to recover.
Sources connected to Sting tell us he was evaluated by several doctors who all agree -- it's just too risky for the wrestler to get back in the squared circle ... so, he's decided to hang up his singlet.
We're told the 56-year-old was formally diagnosed with cervical spinal stenosis -- a condition affecting the nerves that can result in extreme pain and discomfort.