Addison was definitely not a back sleeper...right after bringing her home...she would roll on her side...I finally just started putting her down on her side...she slept much better.
I thought of something else I've done. If they don't like being swaddled but still like tight feeling...I have tucked the sides of a light blanket under the edges of the mattress (mine were usually in pack-n play until 5 months). A nurse showed us this in the hospital because Chas kept coming unswaddled.
If I had known about the weighted blanket at a younger age...Chas would have had one...