I have a light switch that has a single pole switch controlling 1 kitchen light & a 3 way switch controlling a light in the dining room. The wall where the switch was located was opened up about 2' and the switch was part of that 2'. I put a junction box above the walkway so I could extend the existing 3 cables roughly 4'.

I purchased some Romex, tied the black to black, white to white, and grounds together, essentially extending the wires. I grounded the box and all is good.

After hooking everything up exactly the way it was, I have an issue. The single pole has a black wire coming to the top terminal and another black wire looped on the bottom terminal then passed over to the 3 way switch. When power is turned back on, the 3 way works perfect, controllable from 2 separate locations, as well as powering some downstairs lights, as it did before. The problem is the single pole switch that controls the single kitchen light doesn't do anything. When the breaker is kicked on, the 3 way works perfectly and the single kitchen light is on, regardless of what the switch does. When I remove the switch, nothing works because the 3 way was getting its power from the looped terminal on the single pole. If I unhook everything, meaning no wires connected at all to either switch, the single kitchen light turns on. The only way to shut it off is to turn off the breaker.

I replaced the single pole switchave because I was getting 120v on both terminals in both the on/off position. Basically it is just acting as a pass through of sorts for power. Thinking the switch is bad, I replaced it. Same problem.

I took several pictures of all of the wiring beforehand, meticulously labeled all wiring new AND old as to avoid any questions, and still can't figure this out.

I will try to upload my pictures. I have double and triple checked all of my wiring, verifying I wired everything just like my before pictures, and nothing. I am not a professional electrician, however I have done plenty of wiring in the past including an entire garage, ceiling fans, sub panels, etc., so I'm not a complete fool. I would really like to avoid having an electrician come out for something that is probably pretty simple and I'm hoping for some help here. Sorry for the length but I'm trying to give all the information upfront. Thanks in advance.