Sleeping on back?

Emily • Boy 4/14/16 💙 Baby due 11/1/18 💚
So I can't sleep on my right side because my arm falls asleep. Can't sleep on my left side for an extended period of time or my hip starts to hurt bad. I tried a pregnancy pillow and hated it. Putting a pillow inbetween my legs actually makes my hip pain feel worse. 
So my question is... Can I use one of those wedge pillows to put behind my head/upper body so I'm kind of elevated so I can sleep on my back? I'm only 21 weeks so this issue is probably only going to get worse 😫 Anyone have any suggestions??