I agree with Margypops--- and maybe movies and whatnot are just not his thing. The big question is if he functions well on a daily basis or if anxiety hinders him. Emotions are good and he will probably grow up to be that sensative man all woman think they want---- he feels things intensly now and doesn't know how to handle it. That he should learn as he matures. Tell him a story of how you felt the same way some time and how you handled it posatively. Just my opinion.
Is anyone else in the Family anxious could he have learned the behavior? sometimes that does happen, try not to over explain , maybe let him have his feelings without comment ,take a step back try not to be overly concerned that he has a problem.Its not unusual for children not to like the dark, some want a light on.What made him 'over stressed in the movie ...had something happened prior, has he older siblings , does he get on well with him, are they kind towards him .no revving him up or teasing ....