What are bony growths in mouth from behind wisdom teeth growing towards center of palate?

Possibly: If the lump feels stone hard and immovable and it is not painful to touch it might be a Torus Palatinus - a natural and normal part of your mouth. If on the other hand the lump is different than the above description, you should see your dentist and have it checked out.

Boney exostoses: Bumps of bone can develop anywhere in the mouth. Benign, just annoying. But that may not be what you have. Please see your General Dentist or an Oral Surgeon for examination, evaluation, treatment. Any pain, bleeding, or as in your case, swelling, should be evaluated.