Battery percentage decreasing while charging!

Preface: Please forgive my technological ineptitude in advance. I am completely computer illiterate and have embarrasingly little tech vocabulary.

Okay. Help! While my MacBook Pro is plugged in and charging, the battery percentage is going DOWN instead of up. Yikes. If I stop using the computer, close it and let it charge, the battery percentage goes up when I check it after 20 minutes or so. As soon as I start using it while it's still plugged in however, the battery drains (goes down even though it's plugged in). I've pasted the System Report on Power below (I have no idea what any of it means), the recommendation was from another topic forum. Does anyone know what is happening w/ my laptop? It should also be noted that this is a brand new charger (60W MagSafe Power Adapter), but was still happening before with my old charger before it died (the magnetic piece detached from the part you plug into the computer). Also, it seems to be getting really hot (the new one AND old one!) Thank you for your help!!! 🙂

Battery Information:

Model Information:

Serial Number: W0113445WD3BA

Manufacturer: SMP

Device Name: bq20z451

Pack Lot Code: 0

PCB Lot Code: 0

Firmware Version: 201

Hardware Revision: 000a

Cell Revision: 158

Charge Information:

Charge Remaining (mAh): 4428

Fully Charged: No

Charging: Yes

Full Charge Capacity (mAh): 5045

Health Information:

Cycle Count: 496

Condition: Normal

Battery Installed: Yes

Amperage (mA): -868

Voltage (mV): 11995

System Power Settings:

AC Power:

System Sleep Timer (Minutes): 10

Disk Sleep Timer (Minutes): 10

Display Sleep Timer (Minutes): 10

Wake on AC Change: No

Wake on Clamshell Open: Yes

Wake on LAN: Yes

Current Power Source: Yes

Display Sleep Uses Dim: Yes

PrioritizeNetworkReachabilityOverSleep: 0

Standby Delay: 4200

Standby Enabled: 0

Battery Power:

System Sleep Timer (Minutes): 10

Disk Sleep Timer (Minutes): 10

Display Sleep Timer (Minutes): 2

Wake on AC Change: No

Wake on Clamshell Open: Yes

Display Sleep Uses Dim: Yes

Reduce Brightness: Yes

Standby Delay: 4200

Standby Enabled: 0

Hardware Configuration:

UPS Installed: No

AC Charger Information:

Connected: Yes

ID: 0x0100

Wattage (W): 60

Revision: 0x0000

Family: 0x0085

Serial Number: 0x009b16e5

Charging: Yes