I can just tell you that it’s not universal: several doctors I’ve seen and know are very cautious when it comes to pain - both from own experience (“we will go strong with the pain killers for the best two days to prevent stress reaction from the body”) to others (“we need to get the chronic pain under control fast, otherwise there’s the risk of phantom pain developing even after we’ve tackled the issues”) (not verbatim quotes of course but the gists).

It might not even be US generic but a regional or age thing in the doctors you’ve met - remember that usually everyone one of us has only a very limited insight into the whole medical industry.

I’m similar to you in terms of pain tolerance and I’ve walked away from a doctor who talked shit about pain in patients - but I’ve head way better experiences before so that didn’t feel like I’m being stuck with this one medical “professional”.

Wishing you the best of luck though! It’s absolutely terrible when people don’t take you seriously, especially if it’s their job to help you :(