It seems that you are under weight and so facing this problem.
Then you go for good nourishing food with high protein diet,green veges,salads, fresh fruits and dry fruits.
If your weight is alright and no other problem then your problem is because of lack of exercise and active physical work,
Go for walking,running, swimming and jogging.
you start gradually and go for more exercise.
,B complex,calcium supplements
Ok and bye.