I slept on the Purple Harmony and the Coop Adjustable Latex Pillow as a side sleeper with sore shoulders — for me, there's a clear winner

The composite image shows a dark haired woman smiling with her eyes closed as she lies back onto a white pillow on the left, while the right hand side of the image shows a close up image of a beige textured pillow.

Side sleeping puts more pressure on your shoulders and neck than any other position. Finding the right mattress matters, but so does choosing a pillow that keeps your head and neck properly aligned to relieve that joint pressure.

As a side sleeper who used to stack flattened pillows in a (failed) attempt to get comfortable, I know what it's like to struggle with sore shoulders and neck strain. Even the best mattress won't save you from neck strain if your pillow isn't supportive enough.