Ok, I literally tried everything:
1. Deleted my cache on my browsers
2. Use different browsers: firefox, chrome, ie (whatever version that is)
3. Deleted, actually, deleted my wordpress folder via Softaculous on my web server. I have a new installation 5 days ago so I don't actually need to backup anything.
The theme is working Really fine on my localhost. Everything is responding well that's why I'm torn now into thinking WHY won't it work when I upload it on my webserver.
Please can anyone help.
After searching, it seems that I'm not the only who's having this problem. The only difference is that they solve theirs and I'm left alone.
I just need the screen options working on my post page so that I can use the custom fieds.