Would just doing press ups every morning/night help give my pecs nice a nice shape?

Push ups are an excellent start but even though you don't want 6 pack abs etc. it is beneficial for you to work other areas of your body as well. Go and buy 2 dumbbells and look up various exercises on the internet. But do keep up the body weight exercises and try variations of the push up such as decline, incline, Hindu, one arm, diamond and hip. These will help to build muscle over your whole body. Don't expect any instant results, unfortunately. Good luck