4 year old wont sleep

my daughter is 4 years old she wont sleep she always asking if im gonna be in the living room while she is asleep and she keeps sayin goodnight love sleep tight if i dnt say it to her she gets really upset and will say thisover and over again for half an hour even if i say it it she repeats it over and over again. also she wakes up several times in the night and ask the same questions she wakes up screaming sayin she is scared but wont tell me what she is scared of her behaviour has changed she plays up and has even started pullin the dog around she is 4 if i goto my friends house and leave her with her dad she starts to cry and aks if i will be back and asks me to say ill be back but she has really palyed up she throws things around and itis now causing me and my partner to row we have thought about takin her to see a specalist pls can you help many thanks