I can’t speak to pain meds but I travel with an extensive amount of medication across SE Asia even including insulin. Often with a large supply and in 20 flights I’ve never once been asked anything about any of it.
I retired to SE Asia 3 years ago and initially intended to do the retirement visa in Thailand but as soon as o travelled to the neighbors I decided I prefer the variety over any one destination. I do 2 nearly 90 day stays in Vietnam with 2 nearly 90 day stays in Malaysia with a 60 - 90 day stay in Thailand mixed in. I have great accommodations in each place and I avoid visa issues entirely. I also plan my year to avoid the most extreme weather. Things can always change but for 3 years this has worked out great.
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