Burping for the last two days constantly. not drinking soda, no change in diet. there is no feeling of need to vomit. any idea what causes this?

Excessive burping: This needs detailed evaluation to make sure there is no lesion in your intestines causing a partial blockage in your intestines or stomach. Normal burping mostly results from the air we swallow during talking or eating however it is constant, worrisome reasons need to be ruled out. Please see your doctor sooner. If you have pain or fever also then go to ER.