i am not for expensive solutions like water bed and unknown contraptions, but i hope that some knowledge would help in your situation..
most expensive mattresses and beds are aimed to provide comfort for back pain of muscular in nature (muscle cramps and such).. but your back pain appears to be from your spine or from your back bone - and not from the muscles of the back.. so little will be gained from those solutions..
also messaging can be dangerous is many cases of diseased spine - so i highly recommend against massaging or going to a chiropractor without the approval of your orthopaedics doctor..
i assume that sciatica was diagnosed by a doctor because it is a specific sign (yes a sign, not a diagnosis) that only trained people can determine..
sciatica is a sign for something else wrong in your spine and sometimes in your upper thigh.. doctors can elicit the sciatica by holding one leg at a time while bending the knee, then lifting the leg upward and straightening up the knee; of which a shooting pain is a positive sign for sciatica..
think of a lamp with its cable connected to the wall power outlet.. it receives electricity from the wall socket, runs through the cable and into the lamp - simple and normal..
sciatica is when you drop something heavy on the cable (like a heavy sofa).. if the sofa is really heavy, it can definitely damage the cable causing the lamp to short out.. but in your case, the sofa is moderately heavy that still allows some power to run to the lamp; however any slight movement of the cable can cause the short-out at certain positions but not the other..
what doctors test in sciatica, is basically pulling the cable into that uncomfortable position - usually with a straightened knee and with bending the thigh forward more than 60 degrees, because in this position, the doctor is actually pulling the cable that runs from the foot, to the back of the knee and the back of the buttock, and eventually to your back/spine.. and because there is a heavy sofa somewhere between the outlet and the lamp, you cannot pull the cable as much as before; and the cable feels shorter than normal..
so the most comfortable position for your sciatica should be the opposite (a bent knee and straightened hips).. however unless you are a circus acrobat, the simplest way possible is to sleep with your knees bent (forget about the hips for a moment); as the straightened knee matters more in sciatica than a bent hip in sciatica..
you can somewhat ensure that position by putting extra pillows in your bed that prevents you from straightening up the knee and also from bending your thigh too far forward..
now, for the chronic back pain..
the sofa itself can cause back pain especially at night (after a full day filled with movement).. chronic back pain is different from sciatica..
MOST patients confuse sciatica with chronic back pain.. sciatica is a shooting up pain that is felt over the legs and all the way to the back; while most chronic back pain is caused by the abnormal pressure over the spine and mostly felt over the back..
they can overlap but they are not the same thing..
there are some remedies that you can try for chronic pain:
- apply warmth over the back pain area: with a bottle filled with warm water or with one of those warm sticky (exothermic) bandages sold in most pharmacies applied over the back..
the physiotherapy department can offer deep heat delivery that are more effective than the bottle or the bandages solutions - using shortwave (similar to a microwave oven) and infra-red delivery methods..
other solutions: hot baths and sauna..
- take one tablet a day of Neurobion that is sold in most pharmacies without doctors' prescription.. it is not a pain-killer but it helps in preventing early nerve damage (neuropathy).. but inform your doctors because doctors may have already given you something similar..
- and seek doctors help, or request a referral to an Orthopaedics doctor (bone surgeons) if you are not under one.. who may refer you to a physiotherapist for infra-red or short-wave, and who may recommend surgery for a later date..
depending on the cause (on the actual diagnosis), some back pain and sciatica can be relieved with surgery.. however many spinal surgery carry high risk of failure (again depending on the actual diagnosis) that either the pain and the discomfort remains the same, and in few cases, worse than before..
for better answers seek your answers from your treating doctor who definitely know more about your case than anyone of us here.. and all the best..