Trouble in Mattress City?

The past 2 nights on my new mattress have been a mixed bag. My neck feels just fine now, but my back has been hurting a little when I wake up. I didn't pay much attention the first night because I thought it was just me trying to get used to the new mattress. Hopefully that's what it is and maybe it will just take me a week or two to adjust. My back hasn't been hurting very badly, and it goes away pretty quickly after I get up and walk around for a few minutes. I really don't want to have to mess with returning it...

Another thing I forgot to mention about the mattress was that the guy that sold it to me told me that I wouldn't have to rotate it. It is designed not to have to be flipped over, which is good and I think most mattresses are built this way now. But I specifically asked him if it would need to be rotated and he said no. However, the little booklet that came with the mattress says that it should be rotated every 2 weeks for the first 6 months! After that they recommend rotating it every 2 to 3 months! That sure does sound excessive. It would seem like if they could build one that didn't need to be flipped that they could build one that didn't need to be rotated either. I'll bet it's just the mattress company covering their butts and making it impossible to try and make a warranty claim.