Even though you say you are laying on the floor, I do believe those areas receive more sunlight. Shoulders in particular can be hit by sunrays whether you are lying on your back or on your stomach. Additionally, it might not be much, but any time you spend standing makes the shoulders receive much of the light directly.
Germany vulnerable to Russia, really? Russia can barely take on Ukraine but now it's a threat to Germany? Putting NATO missiles in Germany has more to do with US power projection than defense for Germany.
Unfortunately, it does. My late cat would prove it by leaving imprints on the couch.