Lump under chin right where throat starts and connects to chin. more on left side. feels strange. what could be cause?

Lump: Infected tooth. Infected gums. Swollen lymph node. Thyroglossal duct cyst. Neoplasm. Cyst. Hundreds of other possibilities. See a Dentist, Oral Surgeon, Physician, or ENT for examination, differential diagnosis, and appropriate treatment.

Lymph node likely: Any clinician could evaluate this. Meanwhile don't mess with it, but apply warm washcloth for a few minutes every time you wash your face. Very common, don't stress, but get checked if it persists, gets larger or you develop other symptoms. Good luck!