Skinny and underweight

I weight 50kg and I’m 166cm BUT meanwhile I have dense bone structure so I’m only skin and bones. I have skinny legs and very visible bones on my chest.

Do I have any hope for breasts and back to grow or I need to gain weight? I am stuck with this weight and past breast buds stage for years despite good levels. Also my breasts hurt very much if I had a very good day meal wise.