I want to add a junction box for a light fixture. I wanted to add it off of an existing can light. Can this easily done? Also, if so how can a add a separate switch that controls only that new junction box. Thanks

I, like so many, have a room with a receptacle where the bottom half is switched from the wall. There are no ceiling lights and I wanted to add recessed cans. The existing receptacle has a hot and neutral connected to the bottom half of half of the outlet and a hot and two neutrals connected to the top. There are also a number of other hots and 1 white connected together, that I kept the same. I thought that I could copy the top half of the outlet (2 neutral and 1 hot) and then connect a new run of wire to what was previously switched at the outlet and run up to the ceiling to switch the cans instead of the outlet. After I did this, however, the outlet works constantly but when I hooked an outlet up to the wiring that goes to the ceiling (to test it), I got no power. I used a socket tester and got a LIVE EARTH REVERSE fault with the switch on and a red light (far right of 3 lights -- no indication what this means on the tester) with the switch off. What am I doing wrong? I have added a picture. The two yellow wire nuts are the hot and neutral that previously were connected to the switched outlet (bottom of outlet), which are now connected to a wire feeding up to the ceiling. If you need additional info, just let me know. Thanks in advance. It is a lot easier to run from the receptacle than running from the switch (I have no attic access) so I'd prefer to run that way if possible.