Concern about backpack weight and comfort

Assuming that your new pack is appropriate for your torso length, try to adjust hip strap and loosen shoulder straps to carry more of the pack load on your hips. REI advice:

Fit Adjustment at Home

Your new backpack has several straps to adjust your load for greater
comfort. Your legs have some of the strongest muscles in your body, so
the goal is to adjust your straps so that the majority of the load
rests on your hips.

You have four primary adjustment straps: Hipbelt, Shoulder straps,
Load-lifter straps, Sternum strap

Start with about 15 pounds of weight in the pack to simulate a load.
You’ll also need your friend or a mirror to help you check the fit
after each adjustment step. Loosen all of the adjustment straps
slightly before you start.

Adjustments happen in two primary phases:

The Main Event: shoulder straps/hipbelt

The Finale: load-lifters/sternum strap

Thank you for the reply! I actually had it measured and fitted specifically for me at REI, and I think I followed those steps pretty closely. I definitely felt as though most of the weight was sitting on my hips. Does this change anything? Thank you!

Over 15+ years I've tried a variety of backpacks, from the Rick Steves Classic (ca 2000) to the OPEC bag. I have never found it difficult to use a back pack if I pack light enough. IMO, 20# is packing too heavy; after years of fine tuning, my contents are now less than 10#. Note, Lufhansa, a far better airline than the US ones, only allows 17.6# for a carryon. With a 2½# (empty weight) bag, that is only 15# of contents.

I recently got an eTech 2.0 Weekender Junior, primarily for the cinch straps and sternum strap, but the waist belt was a big surprise. Using the waist belt, I can take all of the load off my shoulders and onto my hips. It looks like the REI Women's Trail 40 has a waist strap. Use it.

BTW, 20.25" x 13.125" fits in carryon limits, but 10.5" does not. But it's soft. Just don't pack in full.

BTW, a 20 pound backpack load for a 130# adult is 15% of body weight. During my younger days predating affordable lightweight gear, a pack weight of 25% of body weight was a light weekend pack. While this is a very debatable topic, one article indicates that children's packs should not exceed 10% to 20% of body weight.
https://www.outdoors.org/articles/blogs/great-kids-great-outdoors-blog/how-heavy-should-my-childs-backpack-be/

Your 20# load is in that 10% to 20% range.

As a sort of foot note. Lufthansa's carry-on bag weight limit is 8 kg (17.6#).

It sounds like an issue of adjusting the load-lifter straps. Assuming the hip belt is tight enough, the load-lifter straps can change the placement of the load on your shoulders. Where do you feel the discomfort? If on the front of your shoulders, try shortening the load-lifter straps in a bit, and see if that helps. You want to feel the weight evenly over the top of your shoulders.

Another thing I do when I don the pack is hunch my shoulders to lift the pack while I tighten the hip belt as tight as I can. When you release your shoulders, you should feel most of the weight on your hips and only a little on your shoulders. And it should not feel like it is pulling back on the front of your shoulders.

I am smaller than you---105#--- and a lot older, but I can comfortably carry a 20-25 pound pack for hours, IF it is properly adjusted.

The only backpack I've found to be very comfortable carrying more than 20lb for any period of time is my osprey farpoint 55. It has an internal frame which makes a huge difference in distributing the weight evenly. I could probably walk a few miles comfortably with it fully loaded. It however is not carryon compliant:)

I would experiment with how you are distributing the weight in the pack. I have read arguments for having the heavier things in the bottom of the pack as well as the middle of the pack. See if one works better for you. I have also found people in REI incredibly helpful so maybe bring your packed bag in and ask them for some pointers.

Do you anticipate having to carry your pack for more than 10-15 minutes? I would think that amount of time would cover most trips from train stations to hotels. As with any muscle development, you will get used to it the more you use those muscles but that's also accompanied by muscle soreness. It would be a shame to be sore (or possibly get a strain!) on your trip.

So practice carrying the pack for increasing periods of time and/or work on strength training for your back muscles.

RE: I definitely felt as though most of the weight was sitting on my hips.

You should be able to adjust the hip and shoulder straps such that your shoulders do not carry any significant weight. The shoulder straps would basically be there to keep the pack against your back. If you pack the bag with heavy items close to your back and/or low, your shoulders should not be stressed.

https://www.rei.com/learn/expert-advice/backpacks-adjusting-fit.html

Step 2: Shoulder Straps

Pull down and back on the ends of the shoulder straps to tighten them.

Shoulder straps should wrap closely around your shoulders, but they
should NOT be carrying significant weight. If they are, you'll be
putting undue stress on shoulder, neck and upper-back muscles.

Check to see that the shoulder strap anchor points on your pack are 1
to 2 inches below the top of your shoulders, roughly at the top of
your shoulder blades. If not, then either your hipbelt is at the wrong
level or your pack’s torso length is incorrect.

Vary shoulder-strap tension by tightening and loosening the straps.
Learn how to adjust the straps in small increments so you can relieve
any pressure points or pain during your hike.

Thank you all for the great replies! I will try and adjust the fit of my pack with a new weight distribution to see if that helps. If not, maybe I will go back to REI to try on new sizes or other packs.

As the others have mentioned, the most important factor in choosing a Backpack is to be properly fitted for torso length (which it sounds you have done, assuming the sales person knew what they were doing). Most of the weight should rest on your hips, and the load balance straps used to shift the weight as desired.

Some of the other features I find useful are a stowable harness (straps zip away so they don't get damaged by airport conveyor systems) and a detachable daypack (works great as carry on if the main pack has to be checked, and also for day touring when in Europe).

As you seem to be having a bit of trouble getting the pack to fit, you might also have a look at products from Osprey Packs and/or Eagle Creek. The fit on my venerable Eagle Creek pack is so good, that I can comfortably wear it for an extended time, even if I'm just standing waiting for a train.

I have a Deuter 35+10L backpack that I found to be very comfortable. I am 5'6". It sits on my hips nicely and never felt heavy on my shoulders at all. I had never used a backpack before setting out on my trek so was surprised at how comfortable it was.

That said, you might want to reduce the weight you are carrying as 20lbs is quite a lot, but if you are only walking from train to hotel, carrying that much for 10-15 min. doesn't matter very much. If you are trekking for long periods of time, you will want to reduce that weight to about 10% of your body weight.

I am not accustomed to regularly carrying a backpack!

What do you carry regularly? Maybe start to move some of it to your shoulders so your shoulder muscles gets stronger and the skin on the shoulders get more robust.

It's like running. If you have never run before you don't start with a marathon. You build it up gradually.

I think there's a certain amount of getting used to carrying a pack too. You might redistribute the weight in your pack. When you have it on, look in a mirror. Does it seem to be hugging your body correctly or is it hanging off awkwardly?

I don't use a regular back pack because I've found I rarely carry anything more than a mile, train station to lodging and back, so I don't need something designed for hiking. I need something designed to carry onto the flight so I don't have to check a bag. Regular packs, for me, exceed the max length of a carry on.

One further comment to add is that the two manufacturers I mentioned above have packs which are specifically tailored for women. That may make a difference in the fit.

I carried about 20 lbs for our month long trip. When I was in the airport leaving I was feeling like I had made a huge mistake! It was really heavy. But, I would say that as the trip went on it seemed easier to carry. Now, fast forward 9 years, I'm ready to get a roller bag!

I'd say if your pack hurts after that long to go back and get it readjusted. I really like my Deuter women's pack but it took a few tries to get it adjusted just right. I found that carrying 16-18 pounds was comfortable for me, but more than 20 was not. I also think it's good to go on some practice walks to get used to it, as others have mentioned. If all else fails, REI has a stellar return policy and will do their best to get you in the right backpack.