Mark Wahlberg -- Still a Pain in the Neck

Mark Wahlberg is still feeling the pain after putting his neck on the line while filming "Transformers: Age of Extinction" back in October -- stepping out in Hollywood Wednesday with a neck brace.

Wahlberg didn't hurt his neck while performing some awesome stunt. The actor claims he woke up one morning while filming in Hong Kong ... and his neck just started hurting ... he doesn't know exactly why.

We're told Wahlberg's docs think the brace will help his recovery.

Keep your head up.