Thanks for using Healthcaremagic,
You are known case of hypothyroidism
and taking Thyroxine
supplements, I presume that your thyroid is well controlled.
Now coming to your repeated cough
and cold episodes 4 episode in almost 6 months are not abnormal but you can take care of your immunity to possibly prevent recurrent infection.
Take care of diet, exercise and as per your age if anything is required to supplemented like calcium and vitamin D3
or multi vitamin.
You should discuss with your Physician and get your medical check up so as not to miss anything.
Dr.Akhilesh Dubey M.D.