Hey Nathan 
I just want to add a few things here 
So to gain mass you do need to be in a slight calorie surplus. Your body will not put on any weight if you are not. So, you need to make sure that you are taking in more calories than you use on a daily basis. It is important to also look at the make up of what you are eating, and ensure that you are taking in enough protein. You will inevitably also put on more body fat during this process. This is why the below point is important 
Athletes building muscle will often have to go through cycles of putting on mass (slight calorie surplus) and then of losing body fat (slight calorie deficit). If you are in a constant calorie surplus, you will for sure start putting on body fat, and the longer this goes on, the more body fat you gain.
So, if you feel like this then you need to really change your training goals and start to focus on losing mass. So you need to be in a slight calorie deficit. It’s also worth changing your Training Journey to a more weight loss focused Journey such as Cardio Burn.
