I've worn shoulder holsters for 47 years and have found them comfortable. I'm normal-sized (5'10, 180 lbs, 42" chest, not svelte, and no big belly).
Shoulder holsters without loops to attach to the belt flop around. I only wear SH that have loops or straps that attach to the belt. This model doesn't bind on the back or neck, is very secure, and, except for the nylon strap, all quality leather. It is also a vertical holster which is easier to conceal (I don't like horizontal SH).
My favorite SH is a long-discontinued Bucheimer-Clark. It fits my S&W 4" K frames and now fits well with my CZ 75b.
This one is 47 years old, worn often, and still in top shape. I was fortunate to find another new-old stock BC last November.
I find this SH very easy to carry, excellent for in-car use, and with a jacket easy to conceal and fast to get in the hand.