Why do i keep getting pains in my chest?

well for the past couple of weeks i have been having pains on both sides of my chest and i also get palpitations now the palpitations dont happen all the time only sometime when i have been in bed for about an hour at night they start and sometime in the day.. im about 5ft and i am a petite 18year old but i do no exercise what so ever the most exercise i do is walking up and down the staires and around the house..and have done for the last 3 years.. could this be why i am having chest pain.. am i very unfit or should i consult my gp about them?? thanks if you can help