help me select a bra

Dear ladies,

please help me choose a bra

I had medium sized breast when I was in India. But in the last one year i have gained 7 kg wt. My problem is I feel my breast have grown bigger and at times I feel its heavier than usual. I noticed a kind of sag on it.
Do I need to consult a doctor for this unusual weight feel or
Will using padded bra be helpful to reduce the sag and weight feel ?
Where can I buy those from USA ?
Thank you