Hi yaron,
While you haven’t provided much in the way of specific “symptoms” you are experiencing or the location of your back pain or any specifics about you or which mattress you are sleeping on … it’s not really possible to “diagnose” mattress comfort issues on a forum with any certainty because there are too many unique unknowns and variables involved that can affect how each person sleeps on a mattress in terms of PPP (Posture and alignment, PRessure relief, or your Personal preferences) or any “symptoms” they experience … there is more about the most common symptoms that people may experience when they sleep on a mattress and the most likely (although not the only) reasons for them in post #2 here.
There is also more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel”.
These posts are the “tools” that can help with the analysis, detective work, or trial and error that may be necessary to help you learn your body’s language and “translate” what your body is trying to tell you so you can make the types of changes that have the best chance of reducing or eliminating any “symptoms” you are experiencing.
The type of mattress pad or topper that you may wish to add would would be a preference choice rather than a “better/worse” choice so there isn’t a “best” choice … only a choice that is “best for you”. It would depend on how much additional softness and pressure relief you would need and on the types of materials that you tend to prefer. You can read a little more about fiberbeds or down alternative mattress pads (which use polyester fibers) in post #2 here and post #10 here but the only way to know whether any potential solution will work well for you in combination with your mattress will be based on your own personal experience.
I’m not sure what you are referring to by a “bed board” … could you provide a link?
If you are referring to something like this then it would depend on how the bed board compares to the current support system you are using under the mattress. If you are using a Tempurpedic foundation then it would probably make no difference since your foundation would already be a solid surface non flexing support system that doesn’t need anything else to prevent any flexing or sagging under the mattress.
ADMIN NOTE:Removed 404 page link | Archived Footprint: homedepot.com/p/MABIS-Folding-Bed-Board-552-1952-0000/204653247
The issues you are having with a stiff neck could also be a pillow issue and you may need a thicker or thinner pillow to keep your head and neck in good alignment.
Phoenix