cellphones/salaried/noextrapay/legal?

I have an administrative position, and recenly was provided with a cell phone and pager which i must answer 24/7. The upper administration has not offered any x-tra pay for this intrusion into my personal life. No matter if i’m eating, showering, swimming, opening christmas presents, or in church, I must answer this phone. I get alot of calls. Must they pay me more(even if i am salaried) if i’m to deal with these after work intrusions, what can I do about it, or am I stuck?