Houzz has a feature sponsored by Benjamin Paints, that when you find a photo you like you can click on the icon to the right of the image and it will give you colours similar to the image. You could then take those samples to Sherwin Williams and find similar ones if that was your preference of paint.

Just take one of those pillows to the paint store and have them computer match it.

Why do the walls have to match the comforter? I'd go with a deep purple, with some gray in it, like Benjamin Moore Shadow. I think contrast is more interesting than monochromatic, especially in a room where you change the linens with the season. And remember, it's a room sleeping, and all rooms are black with the lights off.

I have that bedding and i did exactly what was mentioned I took a sham and had it color matched I love my gray bedroom

I would suggest taking the color that matches the bedding and paint large ( I have found 16 inch stripes) work the best. It will be a great contemporary look with out being too matchy. Just paint the stripes on top of the existing wall color.... the photo is an example...

i know gray would be a common paint color to choose here, but I feel its going to be a little dreary. could you do an accent wall behind the bed? or maybe choose another color w/some gray undertones? these blues would look nice, with crisp white trim and ceiling

or if you want to soften it up a bit.

i have very warm, busy hardwood flooring and similar spread I picked in a dark charcoal. I painted one wall black (my headboard is large warm wood w/nightstands) and the other walls a true, light gray.

gray cloud. sweet innocence is nice too. no undertones. they just tinted the white w/black.