I once had a new rheumatologist take me off my meds after running a similar barrage of tests. Things went from bad to worse, as I self-medicated with OTC anti-inflammatories to ease the pain. I knew better, but I added a glass of wine every night to help me sleep. After several months of this bad behavior, a better rheumatologist started me back meds. It took about 6 months to get my liver enzymes back to normal and a year to get the pain under control. I understand why a new doctor needs to run tests, but a good one understands that some of us (maybe a lot!) are sero-negative. A good rheumatologist also will know that you should be treated BEFORE bone erosion occurs, before permanent damage is made to your joints. Yes, there are instances of misdiagnosis, so I encourage you to get another opinion. I believe that you simply must advocate for yourself with your doctors. No one knows your body or your pain better than you.
Maybe a new provider will be willing to listen to your symptoms and try another medication. I also have osteo arthritis in certain areas, and the tendon pain with PsA does confuse things. An experienced rheumatologist should be able to help you!
I feel for you and all of the confusion you have going on right now. You'll no doubt hear more stories similar to ours. I don't think it is all that rare to have your diagnosis questioned by a new doctor, but please seek another opinion before believing it!
Hugs,
Linda