Hi vroomy,
Welcome to the Mattress Forum! 
And congratulations on your new mattress purchase! :cheer: Sleep on Latex is a site member here, and I think you know you purchased a product using high quality componentry.
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. Quite often when receiving a new mattress and sleeping on your side it is necessary to adjust your pillow, and this can be the cause of quite a bit of lower cervical / upper thoracic and shoulder pain, so you’d want to make sure that your pillow is providing you with a relatively neural alignment. You may also, as you mentioned, need a slightly softer/thicker upper comfort layer.
I would first take a look at your pillow, and if that isn’t the issue, my next step would be a phone call to Sleep on Latex and see what advice they might have with your current configuration, as they would be best suited to provide the options that they think will have the best chance of providing the comfort you desire using the materials they have available for you. I would do that before considering adding an additional wool topper, at least at this time.
Phoenix