Welcome to HCM
I would suggest you to ask you is that bump painful??
the bony feeling you are mentioning can be bony over-growth known as palatine torus....its nothing to worry about...it can be left there as it is or you can get it surgically excised.
you didn't mentioned about the pain....well if you are not experiencing any pain then it can be due trauma.
whats your dentition status...i mean to ask are all your teeth erupted....if not then it may be any cyst
related to impacted tooth
done if still problem persists.Consult your dentist
for further query.