Could be. When most doctors refer to tonsillitis, they mean infection (viral or bacterial) of the tonsils at the side of the throat (palatine tonsils). There are also tonsils at the back of the tongue (lingual tonsils) if the location of the pain is truly in the back of the tongue, several diagnoses are possible. Lingual tonsillitis, infected taste buds or if you are a smoker, more serious problems. Ent.