Did Stephen King write the short story martin?

It's about this man who has to undergo an operation and he has another patient in his room, Martin (I think that's his name) Martin has to get a really bad surgery done and keep shouting "I'm not Martin!" The main character wakes up in the night and sees Martin at the end of his bed he just falls back asleep and wakes up the next morning. Then a nurse walks in picks up the clipboard and says ready for your surgery and states what was going to happen to Martin (i forget what). Then realizing Martin changed the clipboard the main character starts shouting "I'm not Martin!" to no avail. Then he looks ove and sees Martin smiling at him. If he wrote this story could you please post a link!!??