Gum pain T_T

Okay this pain has been bother me for almost 5 days now, the pain is at the back of the teeth, the spot where wisdom teeth would usually grow on. But the pain is not ongoing type which make me doubt it's teeth grow pain, in usual mode i just feel a bit weird in the area. The time when the pain really bother me is when i eat. I purposely chew my food on the other side but somehow i feel the pain from it. I certainly don't recall me eat anything hard that could injured the gum nor had i injured it when i brush my teeth. What i do had is i felt a piercing pain when i drink water after i pop it with my finger cos initially i thought it's the tooth!! To be honest, i did skip one or two day didn't brush teeth for the last 2 month cos i felt asleep and usually even if i do wake up around 4am or 5am i won't go brush teeth bah, continue sleep and brush it in the morning mah~

My mum and i have few guess on what might caused it:
1. Wisdom teeth is growing. (even if it is i think it's bad one, since it's kinda at the side, grow side way mean have to cabut lah!!)

2. Could be ulcer since the gum around there feel a bit swollen (now no more) and soft 2 days ago when i pop it to compare with the other side. (could be wrong, you know when guessing, usually brain cincai make stuff up and make u feel like oo got got kinda thing)

3. Eat sth hard and accident injured it. ( i ruled this out cos i didn't chew on hard stuff since i come here)

4. Accident injured it when brush. (no memory of injured there, i mean my front gum bleed from time to time when i floss my teeth but never the back one mah)

5. mum said "is it like my pain" eh dunno what's her pain lah, her one haunted her for very long edi! and it spread one (i mean the pain) but am sure it's not that type since i only feel the pain the most when i chew, no pain when i talk, yawn etc... and it's gum not musscle or bone

I have no idea with teeth and gum lah!