Hi Needsleep,
I appreciate the comments 
In a word (or actually 2 words) … unfortunately no. Memory foam is a chemical composition that is a form of polyurethane which is made primarily of a polyol and an isocyanate mixed in with other ingredients to both make it into a foam and to control the final degree of viscosity and elasticity of the cured foam. There are certainly many variations of polyols that are used, some of which can be sourced from plants (which can partially replace petrochemical polyols), but they are all “chemicals” in the end … even those that are not petrochemical based. There are also various forms of isocyanates used … the most common being TDI and MDI but these too are also chemicals which are not natural in any way. It is generally thought that of the two … MDI is “safer” than TDI (which contains Toluene). The best that can normally be done is to control the amount of outgassing of the finished product and the more harmful compounds that are outgassing to levels below those that cause harm to the majority of people. This is where various testing organizations such as CertiPur or better yet Oeko-Tex can come in handy. Most of the Oeko-Tex polyurethane and memory foams that are certified are made with MDI to my knowledge.
Essentia claims that they have a memory foam made with latex but if you look at this thread in the forum here from a couple of weeks ago where they came to the forum to participate in the thread … at least for a few posts … it seems (to me at least) that their foam is far more likely to be an MDI based polyurethane foam that is using some plant based polyols and has some latex infused in it. Even their latex has SBR in it rather than being NR or natural rubber (based on their own information and some independent test results that I received that tested for various ingredients in their foam). I just wish that they would have continued in their conversation and answered some of the harder questions that have been posed to them by others as well over the years they have been in business and which they never seem to answer satisfactorily. They may be a “better choice” in terms of the ingredients they use in their mattresses (compared to other polyurethane foams at least) but they are certainly an expensive choice and IMO they are not a transparent choice and they don’t do themselves any favors with the untrue or misleading statements on their website either about their own product or other products.
So with memory foam … at least with the current state of technology … there are more and less healthy versions based on the type and amount of offgassing and the testing that has been done on the foam but there are no “green” or “natural” versions currently available. This is why I have been such an advocate of using memory foam which has some type of certification behind it and where the results of the testing is public information (I have personally experienced issues connected toxic outgassing with a certain brand of memory foam and they aren’t fun).
There are also “slow recovery” latex products made by several companies but these have a different feel from the latex infused polyurethane or memory foam products which are being manufactured in several places. One is more latex based and one is more polyurethane based. I also have some hope for some of the newer generation of gel products (made only from gel and not infused or added to something else) which have the visco elastic qualities of memory foam but are also very expensive. I am also following some of the newer types of gel memory foam products which are coming out which are memory foams with gel infusions which are chemically bonded to the structure of the foam rather than ground up gel particles which is added into the foam.
I have had to do a lot more research into the actual chemisty and manufacturing methods of various foams than I would have thought or hoped since I started this site (and I’m certainly not a chemist) just to “break through” and find the truth behind the many stories involving so called “green” or “natural” ingredients but the good news about this is that so far what I have discovered in my research mostly confirms what common sense has told me in the first place. The second bit of good news is that there is a trend in the manufacturing of polyurethane foams that is moving towards the use of less harmful chemicals and manufacturing methods and towards the use of more renewable and less petrochemical based ingredients … but none of them can IMO be called anything close to natural or even “green”.
There are some better choices in the Denver area and the ones I know about are …
Denver Mattress® - The Easiest Way to Get the Right Mattress Denver and many others in Colorado. Regional factory direct manufacturer which also makes a wide range of mattresses of most types that use good quality materials and have some good value. I would stay away from the mattresses they sell which are made by the major brands.
https://www.foamsource.com/ Boulder. Factory direct manufacturer in Boulder that makes a range of latex mattresses with good quality and value and would be well worth a visit.
https://www.verlo.com/ Boulder, Frisco, Longmont. Regional factory direct manufacturer which makes a wide range of mattresses of most types.
http://innomax.com/ Denver, Fort Collins. Smaller national manufacturer which also has several factory direct outlets. Makes mattresses of many different types including latex and memory foam. I would stay away from airbeds which they also manufacture.
https://www.roomandboard.com/ Denver. Retail outlet with a line of mattresses made by Restwell. they carry a variety of latex and memory foam mattresses (make sure you check foam density for polyfoam and memory foam here).
https://www.thenaturalsleepstore.com/ Denver. Ft Collins. Retail direct outlet for several high quality brands of latex and other natural mattresses.
https://boulder.urbanmattress.com/ Denver, Centennial, Cherry Creek, Boulder, Fort Collins. Retail direct outlet for their own house brand (Urban organics latex mattresses), along with a range of mattresses made by Sherwood, Suite Sleep, and VI Springs (ultra premium). Good people who have always been knowledgeable and open about their mattresses when I have talked with them.
https://www.mysleepnation.com/ Denver, Centennial. They carry a range of innerspring, latex, latex hybrid, and memory foam mattresses including their own private label brand made to their specs by Therapedic locally and they also carry a component latex mattress with customizable layers. Very knowledgeable and helpful. Some better quality and value here and their pricing is also “no haggle” which means that you don’t have to “negotiate” to get their best price. Good people
https://www.haikudesigns.com/ Boulder. Retail outlet that carries their own house brand of latex mattresses made by Vymac. Open and informative about the contents of what they sell.
These should give you a number of good places for testing and I would do a little phone research first to give you a sense of the range of choices at each outlet and the knowledge and service that you can expect if you visit them.
Given your side sleeping and shoulder issues … it would be important to have a comfort zone that was both soft and thick enough to give you the pressure relief you need (3" is a good starting point for most side sleepers). Under this of course would be a support core that is firm enough to keep you in alignment and keep your hips and pelvis from sinking in too much. Softer support cores would normally use a thinner comfort layer while firmer support cores will usually need a little thicker comfort layer.
If you have questions along the way feel free to post them here.
Phoenix