i have a bulky chest but i dont work out with weights i just run, do situps and push ups. I just wanna tone down my bulky chest any tips on how i can do that?
Diet. Exercise has nothing to do with the shape of your chest, because you aren't doing anything to make the muscles themselves grow (unless your pushups represent around 80% of your one-rep max or more), and any exercise that you do won't specificlly target weight loss around the chest. You need to lose weight in order to remove fat.
Having said that, you'd be far better off getting onto a good, well-designed weight training workout than continue to exercise the way that you are currently.
Like Jonathan, I think you'd be better off by doing some more training for other body parts, namely your back. all you do is pushups, so you've overdeveloped the chest.
pull ups, lat pull downs, and bent over rows will build up the back to fix the disproportion.