Sure, just like instead of prescribing anti-depressants, we should first do a depression test.
Unfortunately, neuroscience is not at a level where we can actually perform these tests. There is no objective measure to see if someone is in pain, or depressed, or suffering many other psychological symptoms.
Actually, there are tests now for depression. And yes, you can do objective tests like brain imaging to see people's responses to stimuli among other things. What should not happen is for doctors to meet someone for 20 minutes, do nothing but talk to the person and say.. oh, I don't trust them they must be lying. Except, that is what doctors do all the time and there is no scientific basis for their decisions.
Can you point to some tests for depression? A quick Google only turned out some studies, nothing approved and usable in clinical settings (and one of the studies had a test that couldnt differentiate between depression and bipolar disorder).
Similarly, brain imaging for pain is at the research level, and may come with several other risks. I doubt there are such tests that could be used to conclusively prove that someone is or is not in pain.
There are blood and urine tests for seratonin, but studies are mixed on how reliable they are. Since depression can also be accompanied by other factors though, there is a wide range of tests that can help provide objective evidence.
Sounds expensive, wouldn't it just be easier to trust them? I think the bigger problem is if a doctor doesn't know what's wrong or how to fix it, then they disengage.
Unfortunately, neuroscience is not at a level where we can actually perform these tests. There is no objective measure to see if someone is in pain, or depressed, or suffering many other psychological symptoms.