my little guy has this little hard like lump probably grain of rice sized on his right shin

it doesnt seem to bother him if i press it.

Any ideas what it could be ..

it has gotten a little bigger i noticed it ages ago and my DF said Ahhh its nuthin...

but today i felt it again and it has gotten a little bigger - it kind of feels like what a piece of floating bone might feel like... but it seems to be firm in its location..

he has been walking since 9mths old do youthink it could be a result of walking too early ?

im taking him to doctor monday but just need some info now if i can get some.