Two 3mm moveable hard lumps behind bottom front teeth in gums, and one 1mm hard non moveable lump in similar position next to the two moveable lumps?

Bumps: It takes a physical exam to be able to see, feel and take appropriate X-ray to give you an accurate diagnosis. See a dentist ASAP for this.

Lumps: How long have these lesion been there? Since they don't appear to be a normal part of your anatomy, they should be examined physically. Please make an appointment with a local dentist.

See your dentist: There are many causes for the symptoms you described. However for accurate diagnosis see your dentist for examination and x-rays. Otherwise is a guessing game.