A blockage feels like you’ve written yourself into a corner; like there is nowhere to go and all the momentum you were feeling earlier in the story is now crushing down on you oppressively.
It may sound like a zen koan, but sometimes the best way to work through your problems on a script is to stop working on it.
Have something on the back burner, or even a secondary project with its own deadlines. This way, when things get tough, you can take a mental break and go work on something else.
You’re not abandoning your first idea. In taking time away from it, you allow for some distance from the problems that seem insurmountable, and potentially getting inspiration from your other project.
And don’t think that this is an excuse for procrastination. Story problems are simply not something that can be overcome by brute force, but by continuing to exercise your creative muscles in another way, you will be better able to see a solution after you have distanced yourself from the problem.