I started taking centrum gummies vitamins and maybe after a week i started having difficult breathing like asthma.. could be this a side effect?

Gummy bear allergy?: Usually, a reaction to gummy bears would be within 72 hrs, shortness of breath or asthma symptoms, often from the dye used to color them. However, you also want to check other foods/drink taken in or just hay fever pollen from Spring. Use your asthma protection when needed and Nose spray for allergy (Flonase) and if itchy rash, take Benadryl oral 12.5-25 mg po 3x/d. change to dye-free its and see.