
I’m 5’10 and was 129lbs 6 months ago, now I’m 150lbs and still lean. I couldn’t gain for years until I actually locked in. The key isn’t torturing yourself with gallons of mass gainer, but finding a way to get 2500-3000cal through food you enjoy while also getting about 140g+ of protein per day. It will cost a lot more money (my food budget doubled) but be absolutely worth it. Makes it easier to stick with it. Also lift like your life depends on it, YouTube is a good resource to learn more.
And honestly I wouldn’t worry about where you get your calories from as long as it’s not all sugar or something. I eat 2 McDoubles and a large fry after every workout and I’m under 16% body fat. A few protein shakes throughout the day is an easy way to hit your protein targets but make sure to eat some real meat too. You absolutely must be consistent with your calories, count them if necessary.