Why is my router connection seemingly worse on a more free channel?

On my previous question, someone suggested to me to install an app called Wi-fi Analytics. This app allowed me to view that there were 5 other routers hooked up the same channel my router used (11). This explained my constant connection issues when using my internet browser, Minecraft multiplayer, etc. So, I accessed my router and rerouted it to channel 3, because in my area channel 3 seemed clear of other routers.

Now, I'm on channel 3, but I'm going on Minecraft servers and I'm receiving much greater lag than previously. Noticeable large freezes on servers, other players move around sluggishly or teleport around me, etc. The whole reason I switched channels was to avoid issues in which I'm using my browser/minecraft, and my browser loads very slowly, or the multiplayer servers continually state 'pinging' without loading. Now, that issue seems resolved, but this is honestly worse than before.

Why is this happening?

It can be that someone els is accessing your Wi-Fi… Chnage the password just to be safe also. If you have torrents or anything like that downloading in the background this can affect your games too… Try connecting your lan cable and play. If your game still lags then its not because you changed channels

All Wi-Fi channels overlap. By picking channel 3, you are overlapping people on channel 1 and on channel 6 - hence it may be even worse.
All standard (G mode) Wi-Fi uses about 2 channels on either side of the center channel. It is a wide signal. All you are doing when selecting a channel, is picking the "center" of the frequency range.
http://en.wikipedia.org/...N_channels
If you have lots of devices nearby, try to stick with channel 1, 6 or 11 for G mode. If running N mode on 2.4Ghz, channel 3 is the proper choice.