Chevrolet: 1999 chevy cavalier engine problem, chevy cavalier, rocker arms

Question
The car's engine has been knocking some this past week.  Today it stalled on me several times when I came to stop signs.  It will start back up but takes a few cranks.  Had a friend look at it and said that one of the heads was blown.  Does this mean I have to get another engine?  Again, the car starts up but it is knocking pretty loud.  

Answer
Tammy;
HI - blown head ?- well I would have  a cyld. head compression test taken on every cyldender. also check all of the rocker arms.  it could be one of them. if a head is blown you should smoke or water in the oul or oil in the water or over heating, etc.and how is the carb- is the choke closed or not working right ?? you have a lot to check prior to a new motor.  ok....>>>..>><<