Ideas come from everywhere. They're easy. Generating them can become automatic. It's fleshing them out that's the hard part.
I recommend What If? Writing Exercises for Fiction Writers
. First exercise: write the first line of a story. I'm inspired by the Bulwer-Lytton contest of the worst first lines of the worst stories. My favorite there:
"There's more than one way to skin a cat," she mused,
as she pinned its little feet to the dissection board.
Anyway, write funny or enticing or absurd or sensuous first lines.
Second exercise: Write titles to go with those first lines. I came up with stuff like:
ROSES ARE RED, TOO - "What a lovely cock," she whispered, just before biting it off.
HOME ON THE RANGE - I'd been out here too long -- the sheep were looking enticing.
AN ACT OF CONGRESS - As the junior senator futilely plowed my ass with his pathetic little prick, I thought to myself, "The cloud-computing lobby is NOT paying me enough for this!"
BLACK MAGIC WOMAN - I knew I was in trouble when she threw my testicles into the stew pot.
STICK IT WHERE THE SUN DON'T SHINE - The dark side of Mercury is a bad place for an orgy.
HONKY TONK CHIMPANZEES - I knew I was doomed when Bertha blew me her simian kiss.
BRIDGE OVER TROUBLED DAUGHTERS - How much did they need Daddy's love?
BLACK HOLE SUN - When the end of time came, I was enjoying great anal sex.
TEST CASE - Tis better to be Wasserman Positive than never to have loved at all.
Third exercise... well, you'll need to buy the book, eh? It's inexpensive.