1. Ralph found out that his brother cheated on an exam, and he knows he should tell the teacher, but he is hesitating because it’s his brother. He’s caught between a rock and a hard place.
2. The doctor told his patient that he had a very contagious disease and that it was important to tell his family. When the man refused, the doctor didn’t know whether he should call his patient’s family and tell them. He was between a rock and a hard place

Synonym: between the devil and the deep blue sea. Compare to: in a bind/fix/jam; over a barrel; behind the eight ball. Between a rock and a hard place is more dramatic than in a bind and would be used when the problem of choice has no apparent or easy solution.