I think that being happy and having fun are two different things. Most people, when posting on social networks, try to look like they're having fun because you're supposed to look at them and see how cool they are, and how great their life is. I've personally witnessed a girl at a party spending the whole night trying to get the perfect selfie. And yeah, they honestly don't always look particularly self-conscious or satisfied of their life, but I guess that would be a digression. People like Logan Paul might genuinely have fun in doing what they do, and the viewer who looks at that specific part of their life is compelled to think that they must be very happy and carefree to have that much fun. Which is, in turn, a false deduction, because most times you feel the need to have fun and get "amped up" to get distracted from your own misfortune.

"Forcing happiness"and the physical consequences that you describe sound to me more like when someone stays in a situation that's not really optimal for them, like an unsatisfactory relationship or job, and rather than face their shortcomings and disappointments they try very hard to convince themselves that they are happy. And I think it's a very common reaction to a lot of different circumstances during our life, that you can avoid only by being extremely honest with yourself.

Thanks for the post by the way, I love when things get introspective or a little psychological :)