When hunting elk, I tend to leave camp before light and return after dark. So, outside of time napping in the early afternoon sun, I spend a lot of time with a pack on my back. If you are hunting a good distance away from your camp or vehicle, you need to have the essentials in your pack in case of a night on the mountain or an animal on the ground.
This in mind, I'll make a few quick suggestions:
- find a pack that fits well. Not every pack will fit everyone.
- consider what you carry. You need to have the right gear, so make sure you are carrying what you need and not a bunch of stuff you don't. (I doubt that you can get much lighter than your noted weight if you are hunting elk).
- take your knife off of your belt and put it in your pack. Also consider a web belt instead of leather. Cutting down on the stuff that rubs will help. I am not a big guy and tend to have more problems with bruising on my hip bones (and my pants being pushed down) by a fanny pack than strained shoulders from a day pack. My hunting partners prefer the big fanny packs, but they just don't work for me.
Again, it's personal fit and preference, so look around and find what works for you.
Good luck!