Why does my iPhone not charge fully?

I self-replaced the screen to my iPhone 6S Plus. The charging function was working great until I replaced my screen. But now it will charge up to 2 or 3 % but then will slowly drop back down to 0, It also doesn't show me if it is charging or not it will just go up a percent when I have it plugged in but no little lightning thingy. It will charge when dead but when it turns back on it will still just go up to 2 or 3 percent and dwindle back down to dead. I have restarted it, cleaned out the jack, hard restarted it but no fix. I did not get the jack wet. So I really don't know what's going on.