Personally I would say that there is a difference. An award is more like a prize, it could be a certificate or something like that. A reward is more something that you get for doing something right. Sorry if that is confusing. Emm some examples could be:
He worked hard in class all year and as a reward he got some chocolate.
He was given an award for being top of his class.
I would say an award is bigger than a reward. An award may be more public and it could be given out at an event whereas a reward is just something less public. I have just thought of another way you could put it: A reward is given for generally doing something right. An award is given for one event of more significance. There probably is some better way to put it but that is the best i could do