I have a hard pea sized lump on the outside lower right side of my gum. it feels like a bone. i don't have any cavities onthat side. what could it be?

Exostosis: If it has been there for a while, it may be a bony outgrowth called exostosis. If it appeared suddenly see your dentist for an evaluation.

Tori: It is normal to have extra lump of bone which are called tori but you must have that checked by a dental professional.

See the dentist: A thorough examination and a radiograph (x-ray) will be enough to diagnose the bump. In that area it is possible that it could be a tooth related infection even though you don't have a cavity there now. It could also be a benign bony projection. Best to see your dentist for an evaluation.