I don't know if it'll help but my wife was run over by a lorry broken pelvis and back and leg pain for years we tried various mattresses of different types and finally got air mattress so we could adjust pressure to suit and a really thick duvet on top. 

Also got a really soft leather recliner with an air cushion she could lay up comfortably and if wanted sleep on that as well. 

Both helped her. Hope others will join with ideas. 

She has hospital bed with air mattress but she preferres chair mostly. 

Billy