I would imagine the reason your muscles probably feel painful is because your body's stopped eating them and is trying to build them back up again.
You've had very high readings for some time. That indicates your body simply didn't have enough insulin to use glucose as fuel, so during that time, it also used a fuel form that didn't require insulin - your own body.
You've talked about being extremely skinny etc. - that's because your body has been cannibalising your body fat and your muscles to ensure you still have enough energy.
Now you've got insulin pushing that glucose out of your blood and either into your muscles and brain for energy, your liver for storage as glycogen, or into your adipose tissue as fat - in short, the glucose is going to where it's supposed to.
I wouldn't be able to say for definite, but I imagine that's given your muscles a bit of breathing space from being eaten - no wonder they're feeling rough. Plus, the protein you've eaten is now being used to repair those muscles and heal the damage, so you've probably got 'growing pains' too. I would think these pains would pass very quickly.
As a general rule as well in future, it's worth going back to blood sugar as your first principle. Whenever you feel 'off' - be that tired, over-awake, depressed or anything, test your blood sugar. 9 times out 10, the reason you feel 'off' will be related to your blood sugar level.
