What Could Be Possibly Cause Of Chest Tightness Or Heaviness ?

what could possiblyyy be the cause of chest tightness or heaviness just all over? but no pain doesnt hurt to breathe not hard to breathe just very heavy feeling and tight type of feeling in the chest no no pain not in the arm sometimes in my left chest area but not major just this heaviness tight feeling the chest and throat kind of like the beginning of an allergic reaction...i guess it could be from stress