35 yr female have a 2-3mm bony eruption on right side of hard palate just behind third molar which pains on pressing.tonsilectomy at 13yrs.what is it?

Probably: This is probably torus palatinus. Please see your ENT doctor for evaluation and to discuss treatment options.

You Need Diagnosis: It may be something simple such as a small piece of bone working its way out of the gum or some food got pushed under the gum behind the tooth. See your dentist for diagnosis and treatment options.

OS and ENT for Dx: There is a normal bony projection in that area known as the pterygoid hamulus. That area may be tender to touch normally. If you want an accurate diagnosis, i suggest you see an oral surgeon or an ENT specialist or both.