I am 20 year old male who study at college and have stone bladder I want to know that whatever I eat my body do not absorb it and throw it back how much I have healthy food but still I am thin and not gaining height or body nor I have any good height what should I do to do it I also do gym and try to make muscle and body but whenever I pick up more than 4kg my back pain starts and I am not able to walk and pains very badly.