Pain after a night’s rest can be a sign that your mattress is not "just right". If you’re sleeping on a mattress that's too firm, you may notice aches in your hips, shoulders, and knees. Sleeping on a too-soft mattress may cause back pain and prevent proper spinal alignment.
If your mattress feels like it’s sagging or lumpy, the uneven surface can sabotage your alignment. A pillow can help to create a more comfortable and supportive alignment, but it’s only a Band-Aid to a problematic mattress.