First thing is do you have a comfortable mattress? That will determine "how well" you will sleep. Cheap mattress, position won't matter. A mattress over $1k then we can talk.

Pillow plays an important part (thought I was going to talk about sleep, weren't you, not quite there yet). A pillow that's mushy isn't good for the neck, a pillow that is too firm will also strain your neck.

So you have two factors to consider: how good is my mattress and how comfortable is my pillow.

Now we talk about the position you sleep. Lie down and "allow" your body to take the first position without thinking. Your body will speak to you. Everyone's body is different (spine issues, restless legs, body heat issues, etc.) and since you know what clothes, what bedding you best sleep in, just get into bed without over thinking.

Close your eyes and breath 5 deep breaths and relax. Once your body relaxes, it's not about some general consensus on which position is best, it's about what's best for you. Listen to your body, if it's restless, move into a different position. If your knees feel knobby, put a pillow between them.

Your body knows how to sleep, just don't over analyze the experience.

Sleeping on your back I heard is the best but I can't do it. I have to sleep on my side. I know IKEA sells pillows for each type of sleeper and they are reasonably priced. As long as you are getting a good nights sleep why change.

Lately I haven't been able to sleep unless I am in a chair in my living room. I have no idea why. I have to be all squished up on it and it looks like it would be uncomfortable but somehow it's strangely comforting. I'm going to risk sounding really desperate here, lol but in a way it feels like I'm being held. Maybe that's what makes it so comfortable to me?

lol i look much like this but I like to squish really good down in there so my head is on the arm rest and my feet are up in the air.