I have done a great amount of dry practice to attempt to get a consistent position. I am just having issues maintaining comfort for an extended period of time, I am maintaining muscle relaxation and not steering the rifle with muscles. I am 6'2'' with a 6'4'' wingspan and only a 32'' chest, so it is somewhat difficult to find a comfortable position.
To Quote Gary Anderson "There is no hopeless shooter".
There is a position for every body and every body style. Just got to find it. Preferable finding a good coach.
I know I'll catch flack for this, (seems I catch flack every time I mention slings but no biggie, I know they work.
If shoulder hurts due to recoil, let the sling soak up the recoil. It will if you give it a chance. SS is correct, YOU NEED TO RELAX. Relaxation is critical to good position shooter (or any other shooting for that matter).
Get you best position. Relaxed position, use the sling to support the rifle. As SS said, bring your rifle to your head. The left or supporting elbow should be as nearly straight under the rifle as possible. Then fall a tad to the right (assuming your a right handed shooter) and resting on your right elbow. Rest the head on the stock (keeping it straight) you should have a chipmunk look to your cheek. Now point at the target, close your eyes, breath NORMALLY a couple times, now at the bottom part of the breathing cycle, open your eyes and check you NPA. If you aren't perfectly lined up with your sights on the target (Natural Point of Aim), do not force the rifle, pivot using your belt buckle until you're lined up. For elevation move your support hand back and forth on the stock, to get higher elevation, slide your hand toward the trigger guard. to get a lower elevation, slide your hand toward the sling swivel. Adjust the sling to hold it there.
The sling holds the rifle, you don't. Now go back to a total relaxed position, with the eyes close, open them at the bottom of the breathing cycle and see where you're at. Again breath naturally. Shouldn't have to think about breathing at all.
Keep up these adjustments until you naturally fall back (after recoil) to a relaxed position, with a perfect natural point of aim.
Some people use the army man style of prone extending both legs out, not me, I'm more relaxed cocking my right leg up, taking the weigh off my diaphragm. Also helps recover from recoil in rapid fire.
Again, its best if you can find a good coach to help you. The Small Arms Firing School as provided at Perry or the CMP Eastern/Western Games would be best, if you can't do the SAFS then a CMP GSM Clinic would be second best. One taught by CMP GSM Master Instructors. These clinics are conducted all over the country. The CMP has a listing of the up coming clinics. The SAFS and CMP Clinics are quite inexpensive. I don't charge for the Clinics I conduct.
I know the Sniper Hide is mostly about Precision Shooting and about bipods, sand bags 'n such but try the sling, I think you'll find it works.
Edit to add:
I am having some back pain when in the prone position, specifically along the edge of my shoulder blade, both the firing and non firing side. Could anyone give some advice on how to prevent this, or is it typical?
Find a Coach.
In 1999, my wife came off a colt and broke her back, had two rods installed between her shoulder blades. In 2002 they removed the rods but because of the fuzzing of some vertebras she couldn't get into a prone position. No biggie, she hunts either standing or kneeling.
Come Feb 2003 she got activated (Army IRR) and like most back then was sent to Benning for pre-deployment training. Part of that training was qualification. We know the Army's qualification is mostly prone. She couldn't shoot prone.
I went with her to Benning and stayed with her until she left. Being an old has been retiree they wouldn't let me on the range to get her a prone position. So I stopped by the Army Marksmanship Unit for help. Told them my (my wife's) problem, and they said no problem. They sent a guy to the range, worked with her a bit, and she shot expert, no problems what so every.
THERE IN NO HOPELESS SHOOTER.
Your profile said Ohio, scoot up to Perry and sign up for the SAFS. They'll get you your prone position, and help your shooting across the board.