Nagging bitch
A nagging bitch is like a mosquito that won't stop buzzing in your ear even when you slap it and tell it to go away.
'You're not even here, but I'm still texting you about everything.'
'I know you're busy, but I'm still going to send you 100 messages about it.'
'You didn't even reply to my last 50 messages, so I'm sending you 50 more.'