What Could Burning Chest Discomfort Suggest?

hi , sir i am rahul (m) 28 years old 5.10 height and 96 kg weight .before few month i have felt a sudden discomfiture on the left side of my body. there was a feeling or sensations of burning and something disturbing . i also felt almost faint ans short breath. which i managed through deep breathing. i consulted my doctor and he asked eco test . wich recorded normal , my suger lvl , BP, all went normal. he told me not to worry and gave some acidity related medicine but this again repeated after 2 days i again went to the doctor and again the same test was done (ecg) it was again normal and all sugger, bp all was normal . this time he also asked for some more tests like TMT test , chest xrays, eco (ultra sound ) and sonography test all the test went normal . i again got the same problem burning in the chest and i almost had a egc test 12 time and all time the test are normal. now i am having a stiffness in the upper part of my body . since a month which includes stiff chest , solders, upper back . and some times back and both upper jaws . i am really confused that do i still need to be worried about the cardiac problem or its jus a common anxiety. and how long does its usually exists . and how can it be corrected my whole body keep cracking and i keep stretching it like made even while i am walking . i have started swimming, and walking . and also reduced the intake of the outside junk food, sweets, and coldrinks .( i dont smoke and drink . my cholesterol is 186 .i am really not able get out of it and draw the conclusion that weather i need to be worried or not .i do not make any heart attack or any heart related diseases in the family history.plz help me with the reply ..regards rahul