Hello, I am moving home and buying a new bed, but am unsure as to which mattress is best. I will be changing to a kingsize bed. I am 5'8 and 80kg. I have scoliosis. I sleep mostly on my side but sometimes on my back. As an adolescent/younger adult I had a lot of back pains, and found a firm mattress on a good divan base to be the best. Now I still find that bed comfortable when sleeping on my back, but am getting some upper back pain/shoulder pain when I sleep on my side. I don't like the feeling of sinking in too far on a soft mattress, but also I wonder if a firm mattress is maybe putting too much pressure on my upper torso. Your expert advice is much appreciated!