I have Mixed Connective Tissue Disease and I am experiencing pain in the middle of my chest that travels in a line to the right, palpitations that sometimes make me feel that I am going to pass out, shortness of breath and fatigue. I am worried that something new is going on. Is my worry warranted? I am 48 years old, I take plaquenil for the MCTD, cardizem for palpitations, synthroid for thyroid disease, estrodiol for hormone replacement (had hysterectory 10 years ago). I often have aches and pains and swelling. I hate to run to the doctor with everything because lots of times the symptoms are gone by the time I end up seeing the doctor. This symptom, however, seems to be lingering and it's worrying me a bit. Any info you can offer would be appreciated.