Is it ok to lay down and do these exercises?

ClayBubbles

I injured my lower back a couple of days ago due to an intense amount of squatting (with ok-ish form). Is it fine if I lay down on a flat surface and practice or is it better if I try to stand/sit?

highmtn

If your back is injured, you need to ask your doctor about that. If your back were not injured it would be OK, but not optimal. It is best to stand while singing, but ask your doctor what he/she thinks about singing on your back vs standing vs taking a rest until your back is healed.