I have been diagnosed with panic disorder and take lorazepam for it.
Sometimes, but not every night for sure, I get a few palpitations when I get into bed and lay on my left side. If I sit up or turn to my right side it goes away. After a few minutes I can return to my left side with no further issues.
Also palpitations can be felt if I bend over quickly, especially after a meal.
Has anyone else had this experience?

Have you talked to your doctor about this? Doesn't matter if others have experienced this or not, as they aren't you. If this is a concern you should tell your doctor.