Hi kenl,
There will be a break in and adjustment period for any new mattress or sleeping system as the mattress loses any of it’s “false firmness” and the cover stretches and loosens a little and the materials settle and your body gets used to a sleeping surface that is different from what it is used to (see post #3 here). This could typically be a few weeks but it can be shorter or longer depending on the specifics of the person and the mattress (higher density materials can take longer) and it can be surprising to some people how much their sleeping experience can change over the course of the first few weeks.
If you continue to have “symptoms” of soreness or discomfort after the first few weeks then it would be more likely that the mattress you chose isn’t a suitable “match” for you in terms of comfort, firmness, or PPP (Posture and alignment, Pressure relief, and your own Personal preferences).
While it’s not possible to “diagnose” mattress comfort issues on a forum with any certainty because they can be very complex and there are too many unique unknowns, variables, and complexities involved that can affect how each person sleeps on a mattress in terms of “comfort”, firmness, and PPP 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 (at least to the degree that any symptoms are the result of a mattress and not the result of any pre existing issues or circumstances).
Phoenix