on great public demand i would now give the answer..most part of it you won't understand how? but you will when you would study quantum elctrostatics...........

when likeq charqqges come closer they emit photons whose momentum is given as hV/c now these photons go and bombard the other charge exerting force hence they are repled...........

when unlike charges come closer the photons are emiited away from each other hence they move closer to one another hence attraction ......since all bodie don't emit photons the charge is the propety needed........

don't question me why photons are emited since then we would be talking of quantum mechanics whcih is very intricate at our level and high level maths is needed so wait..grow and research

all the best