scarlett, i have exactly the same thing going on at the moment, and have an appointment with my doctor on thursday to see where i go from here - probably a scope down to have a good look :( i have had a poo sample tested and an ecg, both of which were normal.
i take gaviscon just before i go to bed to stop it happening at night - which it does - and always have it on hand during the day to take when i get that 'on the verge' feeling you describe. i find as long as i take it immediately, it stops it.
if i was you i'd go to the doctor and see what he has to say, there are more avenues to explore which should do the trick for you. anything which causes continual pain needs investigating as you just don't know what further damage is being caused.