you are right!! and it also cause hunched over shoulders if you only focus on the front part of the chest. Need to train the upper back as well.............you're placing far too much emphasis on your arms. you should pay minimum attention to your arms since your arms are continually being worked out by the exercises that work out other parts of your body, such as shoulder exercises, pectoral exercises, back exercises, etc.
excessive bench pressing will cause damage to your shoulders.
its also important to train your core, because it will help you with your form as well (ive noticed ppl tire out too soon = weak core)