A lump in the armpit can have many causes. These include swollen lymph nodes, infections, or cysts. Infection can cause fever chills. Iron supplements may cause upset stomach, stool changes, and constipation. They absorb better if they’re taken on an empty stomach before a meal. But if they upset your kid’s stomach, taking it after a meal instead may help. Make sure your giving iron in the doses as prescribed by your pediatrician. Excessive iron intake can lead to serious health problems Signs of an iron overdose include: • severe vomiting • diarrhea • pale or bluish skin and fingernails • weakness An iron overdose is a medical emergency. Consult your doctor for detailed clinical examination.