Hard lump on the lower gums the size of pea. what does this sound like?

2 choices: 1) is an abscess. 2) could be an exostosis of the bone. There may be other choices as well, but those would be my top 2. Best to check with a dentist to be sure.

More important to: Find out what it actually is than what it could be. These things require a one-on-one clinical evaluation. While it could be nothing at all, it could be serious. See your dentist for a definitive diagnosis!

Need more info: Gums is to general of a term for the general public. Most common soft tissue lump you describe is a mucocele ( blocked small salivary gland. Most often inside the lower lip or under the tongue but can be a lot of other places. If associated with a tooth most likely an infection. If near a site a tooth was extracted, even as long as a year ago could be a piece of tooth or bone working itself out.