How old are you? (serious question, not a slight or sarcasm in any way)
It takes hard, painful work to gain muscle mass. You may think you're eating a lot, but you're probably not. And you may think you're training hard, but you're definitely not.
My advise, to keep it very short and sweet? Full-body routines of 50 to 65 minutes, manage your testosterone levels, and get plenty of animal protein and water. Eat and train with serious intensity.