I have small bump inside the mouth... Left side. Just under the gums area. On the soft tissues. It is painless...

Dental evaluation . I guess, you should get a thorough dental evaluation. Good luck !
Small lump. And it could be one of dozens things from a draining abscess to a blocked minor salivary gland, to a gum infection to a neoplasm, etc. To be diagnosed yu will have to be examined. Only then can your Dentist tell you what's causing the lump and whether it will need observation or treatment.