Gravel in mouth corrected post!

I have 1 cichlid that is about 3 inches and has very small gravel in his
mouth!!! Why?

I have removed 1 piece, it was much smaller than his mouth and loose inside,
so he could have easily spat it out himself.

The bottom of his throat is drooping/bulging slighly as if his mouth is
stuffed with food, however when I looked inside his mouth his throat
appeared to have enough room to eat and swallow.

His mouth is too small to look deep inside so I cannot clearly see how many
more stones there are, when I removed the first I could not see any others
until he was back in the water; so they maybe fell to the back of his
throat. His gills are reddened and he appears to breath faster than the
other fish but this does not appear to hinder him. His stomack is never
full looking but neither is it shrunken/distended

He has been like this for about 2 months, I never noticed a bulging throat
the 1st month that I had him.

I think that the fish is a hybrid with a Labidochromis caeruleus, looks
similar but is missing the black stripe on its dorsal fin and the colour is
dark yellow. The fish was bought on its own and the shop said it was
locally bred.

TIA
Dave S