The Boston area has good rheumatologists and you should have no problem finding one. Ask your doctor and then interview the rheumy to make sure he/she has experience treating AI diseases. Check with
www.lupus.org and
www.mda.org.
I have MCTD and have lupus, scleroderma and polymyositis and have been through the mill. Doctors who are part of a larger clinic or teaching hospital are better for complicated cases like yours. Doctors in private practice can be fine but they are less likely to see these cases unless they focus on AI diseases.
UCTD can morph into MCTD or something different. No one can really tell you for sure how it will develop. The symptoms you describe are common with connective tissue diseases and I had most of them and more. Plaquinel is often used for mild cases of lupus but more severe cases usually require prednisone and some other immuno suppressants and even IVIG. There are a variety of treatments and most cases can be controlled but finding the right treatment can be frustrating.
http://emedicine.medscape.com/article/334482-overview
Sorry I cannot give you a specific doctor recommendation but I live in Chicago. However, my granddaughter has ulcerative colitis and was able to find pedicatric specialists in Boston who have successfully treated her.
You might also post on www.myositis.org as there are many with UCTD or MCTD and posters from the Boston area.
Good luck and hope you get a diagnosis and effective treatment.
Bill