I've been a psych nurse about two years, after moving over from medical. I well remember where you are right now. It takes awhile to learn to deal with challenging patients!
When I've had a patient who is obviously "faking it" but suddenly appears much improved, I don't focus on it. I might say something like, "I'm glad you are feeling better" then move on to other things. I will call a patient on their behavior if their symptoms just suddenly appeared when I know they were fine a few minutes prior. For example, a patient recently told me she couldn't get out of her bed, even though she had been up walking in the lounge a few minutes before. Nope, I told her, you can get up. You were just in the lounge. She got up.
Chest pain and S/S of other major medical issues are tricky. I would always report chest pain, c/o seizures, overwhelming pain, etc. Just because they have mental illness doesn't mean that they might not have a heart attack. And yes, I know, 99% of these complaints are requests for attention and/or medication. But is it really worth your license to not report it? I work in a medical hospital with multiple psych units. CP gets reported to the psychiatrist, who almost always consults our medical residents, who of course order an EKG at the minimum and usually labs.
Calling pts on obvious BS stories? Generally I wouldn't, at least until I had developed a good relationship with them. But in most cases it's probably not therapeutic unless their stories and/or behavior is outrageous. Calling pts on excessive use of pain and/or anxiety meds? Maybe, depending on the patient. Again, I would have to have a good working relationship with them. If it's someone with some insight into their issues, I usually mention it and suggest that they cut back. And yes, when a patient shows some insight is exactly the right time to bring these things up. For a pt who calls herself a princess, I might say, "Well, yes, you are a bit of a princess," with a little smile to take the sting out of my words. I might add, "Let's talk about that in our 1:1 after supper. Right now I need to check on my other patients and check my paperwork."
Setting appropriate limits on demanding patients can be a real challenge. On our unit we will sometimes do hourly requests with these patients. Works pretty well. I think it's also appropriate to say to a demanding patient that you need to check on your other patients and it will be 45 minutes (or whatever time) until you can get to their latest request.
Hope this is helpful.