Why do some men play hard to get?

i met a man a couple of months ago he says he fancies me loads and wants to keep dating me his a real nice Gentleman giving me lots of nice compliments.Now what i dont understand is i have to text him first then he will text back a few times then cut me short not even to say got to go now just stops so anyway phone calls are short n sweet too.when i ask him can we see each other he says his working because its shift hours.when were together his nice and cant do enough for me but when were not together it feels like his playing hard to get and its doing my head in..What should i do???