What Causes Burning Sensation On Upper Back And Chest?

I am an endometriosis patients for almost 10 years. Have done laparascopy 3 times and 3 ivf with no success. Since I changed my diet, took food supplement and eliminate meat I am pain free from endometriosis. The last tvs shows endometrial lining appears normal and measures 5.4 mm but both ovaries appear cystic. My menstruation was always regular but only a few months irregular period. The last menstruation was on 27th march and I expect my mense was supposed to come on 24th april as my cycles was always 28 days. Uptil now I haven t had my period and it has been late for almost 3 weeks. I took 2 hpts and they showed negative. I am now having a burning sensation on my upper back and chest, so sensitive even to touch. I thought it might be the position that I sleep but when I change my sleep position the pain doesn t go away. Is this a sign of ectopic pregnancy? I do not have any pregnancy symptoms. I am 37 years old. Kindly help.