Battery Light on and wont go off (battery good and alternator good)

So the battery light suddenly came on. I took it to 5 places including Lincoln and they said battery and alternator was fine. Then I was referred to an electrical place and they said although alternator seemed good it wasnt. so I replaced it. Light still on and car is jerking like it has hiccups. Suggested to me to get spark plugs replaced.
The battery light is still on!!! this is driving me insane. I must sell car father just died. is there a way to get that battery light off?? does it have anything to do with spark plugs? HELP!!!