You go where the volatility and massive order flow is and will be generated into the future. That is why it is ideal to have a working knowledge of many different currency pairs and markets. So you can cherry pick the best opportunities where an explosion of volatility or trend will occur. That is where the money is and not in ranging markets.
Now if the choice is between you cannot handling the pain of information overload and thus quit trading, then by all means focus on just one currency pair. If that allows you to stay in the game, and continue to play while you master one currency pair, then by all means do it. The other alternative is to quit and feel depressed and that is not going to get you anywhere.
However, the very best traders have a good amount of knowledge about various types of currency pairs and financial instruments/markets so they can nail the big market moves and just ignore the choppy markets. So for example, if you felt information overload and just decided to focus on USD/JPY for example, then you would be missing out on huge moves in eur/usd and eur/aud, eur/cad.
You want trading to be as easy as possible and that means you go with the massive order flow that will be generated as those moves are the easiest on the mind and psychology.
You can make a lot of money in choppy/rangy markets. But the even bigger money is in the multi day/multi week moves of 100-1,000 pips.