Rowdy Roddy Piper -- My Neck Is BROKEN!!!

Wrestling icon Rowdy Roddy Piper says doctors at UCLA are about to slash his neck open and take a hammer and a chisel to his neck bones ... after discovering he's been wrestling with a BROKEN NECK.

57-year-old Piper went to his Twitter and explained he had been experiencing neck pain for quite a while -- but didn't think it was a big deal. In fact, he says he was WRESTLING through the pain for the past couple of months.

But Piper says he got an MRI recently -- and when the docs saw the results, they went into "911 mode" -- and scheduled a surgery as quickly as they could.

"So just for the record," Piper explains, "I beat, The Miz, Terry Funk, and 2 others guys with a broken neck!!"

Piper says he's going under the knife in just a few hours -- but tells his fans, "There [sic] using all the smarts they have at UCLA. I SAY BRING IT ON! CUT DEEP!!! I'M NOT AFRAID!!"