Chest Shape Effected After Surgery :How Can Develop Muscular Shape ?

Hello, iam 22 years old male, my name is basit, before 3  4 years , i had operation if my chest , i have extra fats on my chest, i removed it by surgical operation. my chest was like female chest, so i removed the extra fats . now i have no muscles on these sides.

Please tell me how to build mear or muscles ( whatever it called )

thanks. hope u got my question.

ali khan