Honestly you really don't need that much protein. If you are eating 3000 calories per day trying to gain weight, 40% protein macro would mean you are eating 300 grams of protein per day. Absolutely not necessary at all.
If you happen to eat a lot of meat, you may get 300 grams by accident (that would be 3 lbs of chicken, or maybe 2 lbs of chicken plus protein from all your other sources throughout the day). Most normal people don't eat that much meat though, only roided up bodybuilders eating 7000+ calories per day do that shyt
At 150 lbs, you may find it a struggle to eat 3000 healthy calories per day if you are eating that much protein. Its much better to eat a ton of carbs as an ectomorph. Something like 50% carbs, 25% protein, 25% fat would be easier for you to accomplish and wpuld help you on your way to your goals.
If you are struggling to eat enough calories, try buying Quaker 1-Minute Oats and grind them up in a blender with some peanut butter and milk and whey protein or whatever. Pretty easy to make a 700-900 calorie shake that has good calorie sources and will help you reach your necessary 3000 cals
