Very top of my gum hurts, i think it's like a canker sore but there's no bump just kinda swollen. i don't think it's an oral problem, happened before ?

Dental abscess: The most common type of dental abscess is a periapical abscess (tooth), and the second most common is a periodontal abscess (gums) or combination of both tooth-gum abscess, regardless if the tooth has a filing. In order to get appropriate treatment it is important to know the underlying cause for this infection. Rec.: see your dentist for evaluation and treatment.

Swelling: The most common cause of swelling in the mouth is from a localized infection. As infection can spread via blood stream to other areas, wise to address it ASAP. Please see your Dentist for differential diagnosis and treatment or specialist referral.