What is the main conflict in Bag of Bones by Stephen King?

This is a tale about a man named Mike Noonan who unexpectedly loses his wife in the prime of her life. She witnesses a freak accident and on her way to offer assistance, she suffers an aneurysm and dies on the street. The autopsy also shows that Johanna had a secret: she was pregnant. This event knocks the life out of Mike. He barely finishes the novel he is writing, but finds himself unable to so much as begin another one. After years of writing he suffers a block that has him physically ill if he even tries. With four novels in a safe deposit box, he is under little pressure for the next four years, but when that has passed and Mike still hasn't written a word, he begins to get anxious.