Phone won't turn on, stuck on charge screen

Last night, I got my S Pen stuck in the slot and shook my phone a bit to try and loosen the pen. All that it accomplished was turning my phone off, rendering me unable to turn it on again without a charger. I plugged it into a reliable charger and port and waited few minutes. I couldn’t get my phone to start normally, so I held the power button and volume down button for a while. After a logo, it showed the charging symbol within a circle. I waited around 30 minutes before trying again. I received the same symbol, except this time it would constantly fade and reappear with a vibration every 10 seconds or so. After some light care, I was able to get the phone in its charger without problem, and was finally greeted with an LED light. I went to bed, but this morning the phone showed the same symbol with an overcharging warning. I removed the phone from the charger and waited a bit. Now every time I try putting it in the charger, it enters the inescapable charging symbol loop from before. I was able to boot it into custom OS mode by accident, which I then quit out of, but I suppose that doesn’t take much more power than the logo or symbol.

TL;DR: My phone is stuck in a loop of fading and vibrating charging symbols and my S Pen is stuck too.