Hi fulen,
Thanks for sharing your feedback … I appreciate it.
A mattress can take a few weeks to break in and it can also take a few weeks for your body to adjust to the feel of a new sleeping surface that is different from what you are used to but this will generally happen over the course of the first 30 - 90 days or so (usually closer to 30) and then it will “stabilize” (see post #3 here).
There is more detailed information 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 or additions to your mattress that have the best chance of reducing or eliminating any “symptoms” you are experiencing.
The most common cause of lower back pain is comfort layers that are too thick/soft or a support core that is too soft but If you are past the break in period and are experiencing lower back pain then the first thing I would suggest is a call to Scott Jordan so they can give you some suggestions based on their experience with the Oslo and other customers that may be helpful.
Phoenix