The ability to carry all or the majority of the weight on your hips is a function of the specific pack, the weight carried, your body type, fit, and how you adjust the various straps/buckles of the pack. With the right combination of the above, all of the weight can be carried on the hips with the shoulder straps acting only to keep the load from sliding backwards away from your back.
The next time you are out consciously fiddle with the pack... remember that straps loosen and things settles a bit as you hike and move, so you may have to re-tighten the hipbelt, slightly loosen the shoulder straps,etc.
If this does not help, it really may be the pack itself. Although some people can comfortable use frameless packs or other minimalist devices, not all of us can do so. Unless I am mistaken, the Exos does not have a frame that rises above the shoulders and lacks load lifter straps. Without these features, a pack would never be comfortable for me as the weight will eventually load the shoulders. if at all possible, try a pack with a higher frame and load lifters... tighten the hipbelt, snug the shoulder straps, then the load lifters. Then, slightly loosen the shoulder straps and snug the load lifters a bit more. All of the weight should be on the hips.
The Osprey Aether 60 is a good example of a pack that should carry all of the weight on the hips... also try the Atmos.
Lastly, your shoulders may get used to some weight, but mine never do. Listen to your body and find what works for you, even if it is heavier than what is considered ideal or is contrary to what more experienced people use.