Mr. Olympia Phil Heath -- STOP THE GYM SELFIES ... It's Annoying!!!

Hey ... you ... guy or girl with sorta-muscles -- STOP TAKING PICS OF YOURSELF IN THE FRICKIN' GYM ... 'cause it's pissing off Mr. Olympia.

With the gym-selfie craze going global, reigning body building champ Phil Heath says he CAN'T STAND when people stop their lift to shoot themselves in the middle of a workout.

"It's pretty annoying ... they should be in there killing it, you know?!"

Check out the clip -- Heath says you should be concentrating on blowing up your muscles ... and not your stupid timeline.

Listen to him ... he's bigger than you.