Kate posted about how it can be difficult to put characters that you love through pain and suffering. We all know we have to, but I agree that sometimes it's tough, particularly if the character is based closely on someone we know and love in real life. I'd have a very hard time, for example, putting a character through hell who was based on my son. In fact, though, I find it difficult to describe any significant pain for a child in my fiction. I was once asked at a panel at a writing conference if there was any theme I wouldn't touch in horror fiction, and I said I wouldn't torture a child. Someone popped up with, "what if they offered you a lot of money?" That hasn't happened yet, but I'd probably still say no. And the fact is that I don't need to. There are plenty of themes in horror fiction besides the suffering of children. I could write a lifetime without exhausting those themes, so if I chose not to work with a particular theme then neither I nor my readers are missing much.
But no matter what type of character you choose for your fiction, you still have to love them, and you still have to make them hurt. My usual solution for this is to make the characters who suffer the most in my fiction resemble me in some crucial way. I don't seem to have much trouble making a surrogate for myself suffer. Perhaps it's my Catholic upbringing, or my German ancestry (Gramlich means Grief and Sorrow, btw), but I can put a doppleganger for myself through the ringer without much thought or pity. So:
Writer! Hurt thyself!