Hi! I have the same problem and even think i asked the same thing on here before. Sometimes you do not know. The problem a lot of us have is blaming everything on the fibro. At least I was. My cardiologist said if in doubt, have it checked by a dr. When my arm hurts and/or chest pain, i am to go to the er as i have a history of heart attack. When i have a new symptom, i usually start with my primary dr and go on her recommendation on where to look next, if she can not help me. One of the reasons i start there is also because specialists look at and treat the symptoms from thier specialty point of view. Your primary care is more likely look at all the symptoms and know which specialist should be seen.
This is how i look at it.