Hello
You mentioned that your are taking
multivitamin and also iron.
After these drugs , you develop chesty cough , no energy and
tiredness i.e. lac of concentration.
These symptoms may be due to these possibilities , these include:
1 Due to allergy ( like dust , pollen , pests , fumes , spray , smoking ( active 7 passive , sudden change in temperature ). As allergy produces
bronchoconstriction and this causes chesty cough , loss of energy and lack of concentration .
2 Iron tablets or preparation ,sometimes produces such type of symptoms . so may be due to IRON or due to any ingredient of multivitamin .
3 As you didn't mention , why you started these tablets ?
So
iron deficiency anemia may be the cause of such symptoms .
But deficiency of calcium or viramin D 3 , we can not rule out.
So in my opinion get in blood for calcium,
hemoglobin and Vitamin D 3 deficiency.
Still no relief , then consult a doctor and get his opinion.