I have had positive ANAs with a nucleolar pattern (suggesting scleroderma) for 2 years now. And I also have Raynauds, SIBO, chest pain, back pain and low white blood cell count. Even with all of that my rheumatologist does not suspect connective tissue disease.
Before you worry yourself too much, keep in mind that it is a rare disease and that (from what I've read) Lyme itself can cause positive ANAs. I'm not a doctor obviously, but I imagine since your xrays and heart tests are normal that a rhemy likely won't suspect scleroderma, either, but there are other specific blood tests for it that they will likely run.
I suspect my chest pain is most likely anxiety from all this being sick/ unable to hold a job/ unable to digest food/ potential additional scary dx's/ etc etc. Try your hardest to take a few steps back, a few deep breaths and think as positively as you can. Being unable to even eat food right now, believe me, I know how hard that is. But stress/worry/anxiety is only going to amplify all the problems. I try to distract myself by hanging with friends or family as much as possible. I've found that my thoughts don't slip slide down the negative paths as easily when I'm with good company. Cute overload .com is also amazing for quelling anxiety ;)
Hang in there and vent on here when you need to. All of us here know exactly how you feel. <3