achilles,
You need to slow down. Jenny has given you some great suggestions. If it is some sort of arthritic ailment, then seeing a Rheumotologist would be the first logical step. This type of doctor will know what test to run and which blood test would give the correct information to rule in or out any type of auto-immune disorder.
You mentioned being ill either last year or the year before, sometimes virus can lay dormant in your system and then resurface some place else. Take Lyme Disease for example. The first signs of lyme's is flu like symptoms and a strange looking rash. Some people have the rash and no flu, others have flu symptoms and no rash, so they do not get diagnosed with lyme disease, they go on to get better only to develop arthritic symptoms a few years later.
You need to step back, maybe get a hold of your medical records from all of your providers, read them and then bring them with you when you see someone (rheumotologist is a very good start) so that the doctor has a complete picture of what has been done, what may need to be redone and where they may like to begin to determine what is really going on.
Let me know how you are doing
Brenda