I’m a side-sleeper and struggled with your multiple-pillow problem, too. Out of desperation to relieve back and shoulder pain, I recently bought a pregnancy pillow, a giant, tubular U-shaped thing that envelopes the whole body. I’m not pregnant, but it replaces three pillows I’d been using: one under my head, one between my knees and one under my arm. Now when I roll from one side to the other, the switch is easy, so I fall back to sleep more quickly, and I’m definitely sleeping better and waking with less back and shoulder pain. And the shape discourages me from rolling on my back. My wife, despite making fun of me, says I’m snoring less.