You cannot gain mass and lose weight at the same time. High calorie intake is a must for building muscle. Usually winter time is the best time to gain because of the cold weather and baggy warm clothing. I always hated gaining in the summer because when you get heavy, heat kills you.
Also, do not do ANY cardio what so ever when trying to gain muscle. Only work out once a day for 3 days a week using high reps with low weight. Once your muscles adapt you feel stronger and confident you can start working out 4-5 days a week on heavy weights with short reputitions.
Arnold started using steroids at age 16. He also had dedication. You build muscle mass during rest. Rest and sleep allows muscles to rebuild themselves stronger and buiold more red strands. Cardio , example long distance runners are skinny because they build white muscle strands from doing cardio. So do not do two things in one day. If you want to do cardio set aside a couple days to do and thats it.; no weights if you want more muscle.