Can't find the book or title. Parallel universe story

[Gertrude]

Gertrude (this is you)
187 books | 46 friends
Was his name Charlie? He accidentally traveled to another universe that was very similar, maybe while he was sleeping.

Through out the book he learned to travel and discovered that many of his alter lives had followed paths he had not chosen. But any number of things could cause a new parallel universe, even a cough.

Sorry if this is too much info but I thought it was a koontz novel but after going through every single book he ever wrote, I discovered it was not.

I read this book at least 15 years ago.

The setting is contemporary. 2000s probably.

[YouKneeK]

I’m thinking this probably isn’t it – it’s a different character name (Graham) and I don’t remember anything about a cough causing a new parallel universe, and I don’t think it would have happened while he was sleeping based on the premise. But the book I’m thinking of was published in 2005 and does have the premise of the main character accidentally traveling to parallel universes very easily, so I thought I'd throw it out there just in case!

It takes a while before the fact that parallel universes are involved is confirmed in this book, so I’m going to put more details about the book in one set of spoiler tags, and the book title in a separate set of spoiler tags. I really enjoyed this book, but I hate to recommend it or describe it because I feel like it’s impossible to do so without spoiling half the fun I had by going into it blind.

More plot details:
(view spoiler)[The people around Graham think he’s strange. He doesn’t talk much, and he has weird rituals. For example, he’ll lock/unlock/relock a door a certain way, or follow a certain pattern while walking down the sidewalk. He thinks the world is fragile and will unravel if he isn’t careful to do things correctly. He keeps a note in his pocket with his home address, and various notes in other places, because sometimes everything seems to have changed and the notes are the only way he can remember what to do. (hide spoiler)]

The title and author:
(view spoiler)[Resonance by Chris Dolley. (hide spoiler)]

[Gertrude]

WOW. That's a freaking interesting novel.

That is amazing. Not sure how anyone wrote that. LOL.

Not the one I was looking for. On my reading list for sure.

[YouKneeK]

I hope you enjoy it if you do try it. And I hope you find the book you’re actually looking for!

[Gertrude]

It has been at least a decade of searching. I may actually have to write the novel.

I was talking to a physicist friend about it and he asked me the title and author.

The book wasn't where I thought it was and the author wasn't Koontz.