If I lay on my back I can’t fall asleep because I end up snoring so loud that I either choke or I hear myself

I can sleep just fine laying on my side but that’s not good for posture

How to fix this?

You can lay on your side and not have problems with posture if you do it correctly.

How do I do it correctly?

I'm a side sleeper @6'2", 50" shoulders...

You need proper bedding/pillow if I could suggest anything.
Thick mattress topper, good side sleeper pillow, thick duvet.

Side rant: A lot of people go into Bed Bath and Beyond and get cheap when they think, oh no way I'm gonna spend like $700 on bedding--motherfucker you spend 1/3 of your life sleeping and the quality of your conscious life is reliant on your ability to get deep and restful sleep. Make the investment.

Is it possible to retrain body to sleep on back?

Flatter pillow can reduce snoring issues

don't try to sleep on your back, for that is difficult. only try to realize the truth- there is no body. it is only your mind that lies flat or sideways

Lol

True, don't be cheap when buying a quality bed.

I'm a front sleeper with head to the side... :S

Wish I could like posts. This is so true