Share 'How about gaining weight?'

Ok so I am a 25 year old male. I am very skinny and I weigh around 120. I would like to put on about 30 pounds. I just can't seem to do it. I know when I was a kid I was a picky eater. My mom would cook nice dinners and I would just want chicken nuggets or something. Now since I enlisted in the Navy (Now I am out) I can eat anything! It just seems like I can't gain anything. I have to admit I d...