When it comes to pain in back, I have a lot of experiences in this.
Tried all popular adjustable electric beds in past 5-6 years, look at : howdotodo.com/category:s-cape-bed#adjustable_electric_beds
and I can say for sure that "S-Cape" is something best in this field.
It has over 100 positions which are switched easily, you can program to change positions overnight, for me it is like 'live', I call it my 'pet' since helps me with my pains.
Another on is "Reverie deluxe" it is much cheaper ,not so good as S-Cape but for that budget it is simply number 2.
Before me existing S-Cape i spent a lot of money on cheap (under $1.000) adjustable beds and I can tell you that is just wasted money, if I knew I would buy this beauty first day when my back paints started...