My Ryobi weed eater the head of the weed eater is hard to turn and the engine doesn't want to turn it

Problem most likely is that the cable drive for the head is twisted up inside the tube and jamming the operation
you have 2 options
remove the head from the tube and pull the cable out or
remove the tube from the power head and pull the cable out that way
new cables are available from your local mower shop
if the cable guides inside the tube are damaged , consider replacing the bent tube with a straight tube , then you can use more attachments for the head