There are three general ways people end up sleeping: on their back, on their side or on their stomach. One of the factors that contributes to neck problems is sleeping on pillows that are not supportive. If you are a side sleeper, that means your pillow should keep your shoulder and head level.
Shopping for a Pillow
The main goal is to look for something that keeps your spine aligned and comfortable. For side sleepers that usually means a firm pillow, but because our bodies and situations differ, this is a personal choice. For example, side sleepers with neck injuries might need a softer neck pillow, and a person with a heavier head might need more support.
The best way to test a pillow is to get into a position you normally sleep in, and figure out whether you have tension around your neck. If you can't do it lying down, try it standing up, holding the pillow to your head. Unfortunately, when you get the pillow home, it may not work with the mattress; for example, if you have a saggy mattress, your head will no longer be in alignment. So be prepared to continue the search.
Look for a filling that is known for its support properties. You can go for memory foam and latex, which are both malleable materials that slowly mold to your head. Another choice is grain pillows, which can be adjusted manually to make a comfortable pouch for your head.
Look for a contour shape that might work with your head and shoulders. Neck pillows come in all sorts of contoured foam. Some have a depression in the middle so that the head is cradled in a dip, while the neck is supported. Others are padded strategically so that your neck is supported by extra fill.
Try putting a pillow between your legs for better alignment. Without a pillow, your knee will sit on top of the other and press into the mattress forcing your spine to curve to accommodate that position. Another type of pillow some side sleepers favor is the body pillow. It simply combines the head and knee pillow for support. However, if you find yourself throwing one leg over the pillow and twisting your lower body, you might want to give it up; it can result in back pain.
Don't neglect comfort. A pillow may have the right contours but the materials might be uncomfortable; for example, you may be distracted by the sound of buckwheat hulls. Look at reviews about various materials such as memory foam and latex, which can provide the range of complaints people have reported about various fills.