I've had all 3 issues since I was a teenager. From my perspective, doctors in the USA don't give a shit about any of them.
Back pain? You need to exercise more and lose weight. Great advice, of course, but ignoring the fact that it was an issue even when i was at my skinniest and most active.
Constant anxiety? You need to do breathing exercises. Oh, that didn't work for you? That's not possible, you're doing them wrong.
Sleep problems? You need to exercise and lose weight. Great advice, of course, but it ignores the fact that my sleep issues were a problem even when I was at my skinniest and most active.
This should not be assumed at the expense of a thorough evaluation at onset but so much of this is by design with our current way of living.
Potential remedies once more serious conditions have been ruled out is regular walks, reconnecting with nature, decreasing screen time and embedding oneself in a sense of community (which will mean different things for different folks).
Humans simply don't live a balanced lifestyle anymore (especially when it comes to caloric intake and activity). Restoring that balance should be the first step before we start throwing pharmaceuticals around.
If you can't sleep well then it's worth getting a sleep study done. I did one and was diagnosed with both sleep apnea and insomnia. I was prescribed a CPAP machine for the sleep apnea and Trazodone 100mg for the insomnia and it's helped a lot. I sleep so much better now.
Edit: Trazodone isn't the best solution for everyone, and can have potential side-effects, but it works very well for me. My point is that you should get a professional diagnosis from a medical facility that specializes in sleep.
Trazodone was originally a medication for depression, but other antidepressants are more effective these days, and now it's mostly prescribed off-label as a treatment for insomnia. It doesn't work well for everyone, but it works great for me. I don't encounter any side effects, and I can fall asleep faster and stay asleep longer.