I bought one from gossamer gear for my hiking pack. Works great if you are into that sort of thing. I am right handed and like my shoulders slick while hunting for gun stocks (right) and bow strings (left).
I’m doing a lot of backpack training right now. And on the longer hikes I’ll put on a pod cast, and it would be nice to have my phone up closer to my ear. Also I carry a dog collar remote. So that would be a great place for it as well.
Mystery ranch makes the sling pocket for their fire packs that could probably work for that, or get yourself an otter box or lifeproof case and use the belt clip on there
I was searching for something similar a week or so ago, and just typed in "backpack shoulder strap pouch" on google and amazon and the one I liked the best was one called the "Jack Wolfskin Gadget M E-Pouch". The gossamer gear one also looked good.
Just make sure it has straps to hook to a vertical strap rather than a horizontal one.
Why can't one of our many talented guys who se on here make a universal pouch big enough for most cel phones with a firm back and elastic front, much like the top of a AGC bino pack? Should be cheap, simple, and could have a couple universal attachments on the back....