The pain you are referring to is called Delayed Onset Muscle Soreness, DOMS, in the trade. Google it.

Are you sure you’re going to failure on each rep? And I mean failure.

Also, you should be mixing up your routine as previously mentioned. Also, you must stretch, I know the benefit doesn’t seem immediate but when you have a nagging pain that just won’t go away you will understand. I predict it will be your shoulder. Most folks train chest and don’t stretch it, eventually tight chest muscles pull the shoulder forward and hey presto, nagging shoulder pain.

Theoretically you shouldn’t be training every day. 2 or 3 on and 1 off seems to be the universally accepted standard. Your body grows when it’s resting. You also need food to grow and repair, so diet is key. In order of improtance: diet, rest, exercise. I can’t stress enough the importance of good diet, really is the key to being bigger and stronger.