You are lucky, getting it in Pattaya is almost impossible, I managed to get Fascino to stock it in Pattaya for a while but they won't stock it anymore and before that I used to get it sent from Bangkok but that source dried up as well.
I knew the price has drastically increased as much as a few 100%, I used to buy the 1000 tables bottles at 500 baht but last bottles I got was 2200 baht for a bottle of 500. I have heard of a few reasons why, including internet companies stockpiling, swine flu increasing raw material cost and new customs law making it more expensive to import Desiccated pig thyroid from China though I can't see why they would need to import it with all the pigs in Thailand.
Doctors will normally usually only prescribe Levothyroxine which doesn't work as well for many people with Hypothyroidism, which I have had for over a decade now. The natural Desiccated thyroid was quite easily available in Thailand, since 3 of the most common brands where made here, Thyroyd-S, Thiroyd and TR-T but in the last year or so it has become increasingly difficult to get. Tried second road but no luck.