Since my childhood, i have pectus excavatum and my hands and legs are very thin even though my weight is 47 48 , i have bow legs too , my shoulder seems little bit muscular but my hands are even thinner as compared to the children of 15 -16 age , is it due to vitamin d deficiency or something else , now it's effecting my self esteem as i am very thin and a college going student despite of eating all food , my boding isn't becoming healthy like a normal 20 22 years old boy