thanx for sharing your concern,
as you have mentioned that your gum is hurting badly and sore to touch there could be many reasons for this. like..........
CLASS FIVE DENTAL CARRIES,
SOME GINGIVAL POCKET
DUE TO PLAQUE, CALCULUS AND OTHER IRRITANTS ,
TOOTHBRUSH TRAUMA etc
all these are differential diagnosis on your chief complaint.
but friend, i think you have not noticed , there could be a very minor apthous ulcer too.
which has appeared two weeks back, healed on its own and has appeared again.
this is also quite painful .
for this you don't have to worry,
you can take capsule BECOSULES one tab per day for fifteen days .
also get an xray done for the concerned tooth and gum, there might be some pathology underlying it
this should help.