Why won't my phone charge?

It's an LG Android Ally by Verizon. The phone charged yesterday night perfectly to 100% charge. But yesterday the battery seemed to die quickly so I plugged it back in and the phone said it was charging, but the percentage was going down, so I pulled out the battery and put it back in and it charged again back to 100% as the day continued the charge decreased again so I plugged it in for the night. I woke up this morning and saw that the charge was only at 26% so I pulled out the battery and let the phone cool down for about 3 hours and then replaced the battery and plugged it back in. As I have been checking in on it through out the day the charge has gone from the 26% to 16% to 8% to now at a 1% all the while saying it is charging! I have it still plugged in and it remains turned on and useable as long as it is plugged in. Any advice or tips would be wonderful! Please and thankyou(: