What should I do if I do something sweet and my boyfriend doesn't respond?

The only way you can get him to chase you is to let him chase you. By that i mean, you stop giving him all the attention, and wait for him to miss you, and when he realizes hes not getting the attention he continuously gets, he'll do it himself. And he'll pay you more attention. But don't stop talking to him completely, just back away for a while and be patient, it might take him a while to realize that he's not getting your usual attention, so he'll give you some to receive some, but let him come to you and realize why he wants you and why he likes you. Good luck :)