Performing heavy resistance exercise is the best way to develop muscle mass. When you place your muscles under enough stress it causes minor muscle tares, this is what causes the muscles to be sore the 
next day.
The amount of soreness tends to reduce as the muscles get accustomed to exercise, however the soreness may never completely go. Heavy weight training is not the only way to trigger muscle growth, exercises like running, cycling, swimming and rowing can also trigger muscular development.
Compound exercises for muscular development
Muscle Development
When you train hard enough and those muscle tares happen, your body needs to repair your muscles to better cope with further muscle stress. Your body achieves this by making those muscles stronger. If you continue this pattern your muscles will get stronger and therefore they will get bigger.
Regular stress on the muscles also causes the body to release more nutrients into the muscles therefore resulting in better physical and athletic performance. This nutrient release will also aid with quicker recovery times and increased muscular development.
There are two main forms of muscle development, these are hyperplasia and hypertrophy. Hyperplasia is an increase in the amount of muscle fibers, and hypertrophy is an increase in the size of your current muscle fibers. The type of development you gain is dependent on the type of training that you do.
Your Diet
What you eat plays a big part in muscular development, you need carbohydrates for energy so you can train hard enough to trigger muscle growth. You also need protein because this is responsible for repairing your muscles and making your muscles stronger and bigger. It’s recommended to eat protein throughout the day, as the body doesn’t store protein and the body can only use a certain amount at any given time. If you consume more protein than the body can handle the excess protein will be wasted.
I would recommend eating a good source of protein with every meal, 4 – 5 meals spread out during the day. Calorie consumption also needs to be increased, how many calories you require is dependent on how tall you’re, for example a male who is 5 foot 8 inches would require about 3000 calories minimal to make good gains in muscular development.
