For some reason when I play the acoustic now sitting upright my right starts to fall asleep as I play. What can I do to prevent this?
ehm, don't put too much pressure on your wrist or forearm.
I think "your arm falling asleep" means your blood can't get through right so your body warns you that your hand is running out of oxygen...

I fell asleep on my arm once, scariest thing that ever happened to me. I thought it was kill.
I had this, which ended up being muscle strain, light tendinitis and other nasty stuff. Go to a physiotherapist for a general check-up.
your most likely cutting off blood flow somehow, which isnt that serious, you just need to reposition how you are holding the guitar.

But.. it could also be other worse things
When you are sitting, don't let the guitar angle into your upper chest....this forces your right arm (assuming you are "right handed when you play), to angle over to attack the strings. Keep the guitar at a parallel to your upper body.

Try standing with a strap when you play, .....this will force the parallel condition and keep your right arm from going into a weird angle on the back bout.

"I was so much older then; I'm younger than that now"

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