also bitchen, "good," teen/surfer slang attested from 1950s, apparently from bitch (v.) in some inverted sense. The noun meaning "complaining" is attested by 1945, U.S. armed services.
Entries linking to bitching
bitch v.
"to complain," attested from at least 1930, perhaps from the sense in bitchy, perhaps influenced by the verb meaning "to bungle, spoil," which is recorded from 1823. But bitched in this sense seems to echo Middle English bicched "cursed, bad," a general term of opprobrium (as in Chaucer's bicched bones "unlucky dice"), which despite the hesitation of OED, seems to be a derivative of bitch (n.).