Oh I would like to get bigger! Not sure anything helps you get smaller, or bigger actually. But push ups are the gold standard for your chest. And they work shoulders and arms at the same time. If you can't do one yet, I read a great idea once where you just slowly lower yourself down repeatedly until you build up the strength to push back up too. You can also do chest presses and chest flies. Try googling those. For my arms (when I am not injured like currently) I also do all sorts of strength exercises. I think you can find all sorts of ideas online. Good luck