Your probably doing it right but pushups are too easy for you. you need to do weight training to actually feel a chest burn e.g. Dumbell press, incline bench press etc
I used them for about 3-4 weeks and that was about 6 months ago haven't been using any types creatines for a while now. What creatine are you using ? Or have heard good stuff about it?
I used Cell-Tech Hardcore by MuscleTech and Size on by gaspari. My diet is clean eating my calories and macros for bulking but need a good quality creatine to get faster gains.