Hold/put a gun to somebody’s head
Definition 1 of 2
Pro Tip 1/3Figurative sense
Used to describe extreme pressure, not actual violence. 
The deadline was so tight, I felt like my boss had a gun to my head.
Pro Tip 2/3No physical threat
The 'gun' is symbolic for any sort of ultimatum or coercive tactic. 
The contract had a huge penalty for canceling, it was like they put a gun to my head.
Pro Tip 3/3Emotional impact
Indicates that someone feels trapped or cornered into making a decision. 
I didn't want to sell my car, but the financial situation held a gun to my head.