Should i try to get my ex back if he is willing to change?

People can and do change. You broke up with him because he wasn't putting time and effort into your relationship right? What worries me is that he wasn't doing these things because maybe he really wasn't that into you.(I don't know how long you were with him) I think you should tell him you want to talk to him, even if it is just to get it off your chest, so you can try to get over it. Who knows, maybe he wasn't aware of your unhappiness. Trust me, communication saves lives, and relationships. If you think you still want him, then talking to him about it can't hurt anything, especially since now, you aren't with him, so he can maybe see from the outside how he was acting.