By pass the softener and flush the lines and see if the odor is stil present. If so then it is coming in from the well. If not then sanitizing the softener is in order.
Shocking isn't always bad but IMO it is overdone from a water quality and a few other points of view. Shocking a well can cause water quality problems that without testing for THMs (trihalomethanes) or specific DPBs (disinfection by products) you won't know exist; or were created. It can also cause pump problems and water treatment equipment problems that should be by-passed first and then sanitized independently and properly. Shocking can also cause migration of dirty chlorinated water to neighbors' wells which if that happens upsets them more than a bit... Shocking can also cause other problems in the well, like bacteria caused slime production and encrustation formation which can lead to reduction in recovery rate and submersible pump problems. Chlorine alone can not penetrate the slime or encrustations and using more chlorine raises the pH of the water and pH above about 7.2 results in chlorine being less effective. It also becomes less effective in the future due to the slime and encrustations.
If you shock, FDA approved chlorine pellets are best but non-scented regular bleach works but Chlorox labels say not for water treament... Do not use pool chlorine.
Quality Water Associates