Hi Cattoo,
Iâm sorry youâre not sleeping comfortably on your new Simple Sleep mattress and topper. 
While I canât diagnose comfort issues or pains via an online forum, I can provide some general advice that might be useful.
First off, there is some information about the many different symptoms that people may experience on a mattress and some of the most common causes behind them in post #2 here that may be helpful. If you have some soreness in your hips, this can commonly be an issue where there is not enough surface comfort to contour and cushion around your hips when you are on your side. Granted, youâve only had your mattress for seven days and is usually takes a few weeks for people to begin to adjust to a new mattress, but your mattress does use a quite firm 6" Dunlop latex core, with 2" of plush Dunlop latex on top, and it could be that you need more surface contouring.
Based upon some of your previous comments and those in this post (asking about blends, density/ILD relationships), I think youâre really focusing in the wrong areas and trying to predict comfort based upon specifications that you donât completely understand (I know it can be complicated B) ) . Unless you have a great deal of knowledge and experience with different types of mattress materials and components and their specs and different layering combinations and mattress designs and how they combine together and can translate them into your own âreal lifeâ experience that can be unique to you (which would generally be a very small percentage of people) ⌠I would tend to avoid using complex specifications to try and predict how a mattress will feel or perform for you. When you try and choose a mattress based on complex combinations of specs the most common outcome is âinformation overloadâ and âparalysis by analysisâ. Even the best mattress designers in the industry are often surprised at what a mattress they design âshould have felt likeâ based on the specs when they design it and what it âactually feels likeâ when they test out their new design.
The only way to know whether any specific mattress design or combination of layers and components is a good âmatchâ for you in terms of comfort, firmness, and PPP with any certainty will be based on your own careful testing and/or your own personal experience when you sleep on it.
As you are local to My Green Mattress and visited the showroom to pick out your first mattress, I would suggest another visit there and express to them your concerns and symptoms with your current configuration, and I would strongly consider their advice as to what direction they think you might want to move. They will have the expertise of working with their componentry and people in similar situations to help offer suggestions that they truly think will help solve your problem. If you choose to do this and a new configuration is derived, I would make sure that you take some time in comfortable clothes and test out the configuration suggested on your side and see how it feel upon your hips, and I would focus on this experience versus density/ILD or blends of latex (you are selecting products using good quality and durable materials) as nothing can replace your own personal testing.
Form a distance, that is the best advice I can provide and the (simplified) direction I would tell you to consider.
Phoenix