little yellow rock shape

hii...i have recently been coughing up tiny pea size hard yellowish subtances. That when i crush these little rocks they smell HORRIBLE. I was wondering, if any1 knew wat these things are, and if there is a way to get rid of them?

p.s. I have been on anti-biotics for da past 2 years, and i am scared to get off of htem cause, my Acne will come back with vengens.


thank you and god bless