MY LENOVO ANDROID PHONE WON't TURN ON

So okay, i just installed 3G into my phone, and then i used it for long hour of time, so it went to low battery like about 3% so i put in the charger and then left it for a while, but then i began reusing it, and then it was all fine because i use my phone with the charger in it all the time, and nothing happens, but then my phone unexpectedly shuts down without warning and i can't turn it back on… What can i do without going to the repair shop.

It is possible that the active phone was using more current than the charger could supply and so you continued to discharge the battery completely. Leave the phone alone in the charger for several hours to give it a chance.