About once a month I run across the idea that you must suffer for your art. There are a number of variations on the theme, but one of the more common one for writers is of the sweating blood variety—writing is easy, I just stare at the blank page until the blood I'm sweating spills all over it. This drives me crazy. So does the oft quoted Everybody hates to write. Everybody loves to have written which is usually attributed to Hemingway.
If it hurts that much to do something, it's probably not a good idea. (Okay, there are subset of writers who can't not write and who hurt themselves in the process. This has always struck me as terribly unhealthy, but everyone's got their kinks.) However, excluding the compulsive writing masochists, if writing doesn't make you happy, why are you doing it?
The monetary rewards are low, arbitrary, and rare, so you really need to find the process emotionally rewarding if you're going to do it. I write because there’s nothing in the world I’d rather do. I love every minute of it, from the conception of an idea to fussing with final drafts. Yes, I love having written, but I love writing more. It brings me joy. That's why I do it. It's actually quite simple.