Is it bad to sleep on my shoulder?

Yes. : Yes, sometimes it can cause issues with your movement and mobility of your shoulder.

No, as long as . . ,: Like everything the way we sleep has developed over millions of years. Our bodies employ many strategies during a sleep cycle to protect us. One of those is to keep shifting position so that we don't apply constant pressure at a single point that could compromise circulation and create a bed sore. Interference like getting very drunk and passing out in one position can defeat this defense.