The Title
User Hal-900 in Washington state wrote in his IMDB review "And I still have not figured out the film's title."
It's quite simple. The first scream is the scream of a victim when he discovers his right limb has been amputated. The second scream is when he discovers the next day that his left leg has been amputated.
And there you have it: Scream and Scream Again. Which was shortened from the original title: Scream, Scream, Scream, and Scream Again.
Or it could've just been named after the cheesy song performed by the Amen Corner.
Sirs?