Hi Your investigations done for the chest pain was reassuring. That ruled out heart problem. Your can still have an atypical chest pain called prinzmetal angina, which is basically spasm of your coronary arteries. But more worrying is sweating excessively at night and weight loss. This can be due to infection like tuberculosis outside the lung and in few occasion due to disease of the lympnodes (lymphomas). I am not sure where you live, but you need to have certain blood test like ESR, CBC, Liver profile, LDH, Beta 2 microglobulin. CT of the chest abdomen and pelvis. If there is any enlarged lymph node larger than 2 cm in size, you need a proper tru cut biopsy and NOT a needle aspirate which most often give false negative pictures. Get it checked out soon. Hope it is nothing serious. Best wishes.